diff --git a/.editorconfig b/.editorconfig
index 9b6d6a510c..5e6d3f6649 100644
--- a/.editorconfig
+++ b/.editorconfig
@@ -145,7 +145,7 @@ dotnet_diagnostic.IDE0056.severity = warning
 
 # IDE0057 Use range operator
 #csharp_style_prefer_range_operator = true
-dotnet_diagnostic.IDE0057.severity = silent # Requires C# 8 - TODO Consider enabling
+dotnet_diagnostic.IDE0057.severity = warning
 
 # IDE0070 Use 'System.HashCode.Combine'
 # No options
diff --git a/OpenRA.Game/Exts.cs b/OpenRA.Game/Exts.cs
index 57ced8a9c3..3fae7d9be1 100644
--- a/OpenRA.Game/Exts.cs
+++ b/OpenRA.Game/Exts.cs
@@ -590,8 +590,8 @@ namespace OpenRA
 				return true;
 			}
 
-			Current = span.Slice(0, index);
-			str = span.Slice(index + 1);
+			Current = span[..index];
+			str = span[(index + 1)..];
 			return true;
 		}
 
diff --git a/OpenRA.Game/FileSystem/FileSystem.cs b/OpenRA.Game/FileSystem/FileSystem.cs
index e2c598e9ce..16d775310d 100644
--- a/OpenRA.Game/FileSystem/FileSystem.cs
+++ b/OpenRA.Game/FileSystem/FileSystem.cs
@@ -85,14 +85,14 @@ namespace OpenRA.FileSystem
 		{
 			var optional = name.StartsWith("~", StringComparison.Ordinal);
 			if (optional)
-				name = name.Substring(1);
+				name = name[1..];
 
 			try
 			{
 				IReadOnlyPackage package;
 				if (name.StartsWith("$", StringComparison.Ordinal))
 				{
-					name = name.Substring(1);
+					name = name[1..];
 
 					if (!installedMods.TryGetValue(name, out var mod))
 						throw new InvalidOperationException($"Could not load mod '{name}'. Available mods: {installedMods.Keys.JoinWith(", ")}");
@@ -211,9 +211,9 @@ namespace OpenRA.FileSystem
 		public bool TryGetPackageContaining(string path, out IReadOnlyPackage package, out string filename)
 		{
 			var explicitSplit = path.IndexOf('|');
-			if (explicitSplit > 0 && explicitMounts.TryGetValue(path.Substring(0, explicitSplit), out package))
+			if (explicitSplit > 0 && explicitMounts.TryGetValue(path[..explicitSplit], out package))
 			{
-				filename = path.Substring(explicitSplit + 1);
+				filename = path[(explicitSplit + 1)..];
 				return true;
 			}
 
@@ -228,9 +228,9 @@ namespace OpenRA.FileSystem
 			var explicitSplit = filename.IndexOf('|');
 			if (explicitSplit > 0)
 			{
-				if (explicitMounts.TryGetValue(filename.Substring(0, explicitSplit), out var explicitPackage))
+				if (explicitMounts.TryGetValue(filename[..explicitSplit], out var explicitPackage))
 				{
-					s = explicitPackage.GetStream(filename.Substring(explicitSplit + 1));
+					s = explicitPackage.GetStream(filename[(explicitSplit + 1)..]);
 					if (s != null)
 						return true;
 				}
@@ -263,8 +263,8 @@ namespace OpenRA.FileSystem
 		{
 			var explicitSplit = filename.IndexOf('|');
 			if (explicitSplit > 0)
-				if (explicitMounts.TryGetValue(filename.Substring(0, explicitSplit), out var explicitPackage))
-					if (explicitPackage.Contains(filename.Substring(explicitSplit + 1)))
+				if (explicitMounts.TryGetValue(filename[..explicitSplit], out var explicitPackage))
+					if (explicitPackage.Contains(filename[(explicitSplit + 1)..]))
 						return true;
 
 			return fileIndex.ContainsKey(filename);
@@ -279,7 +279,7 @@ namespace OpenRA.FileSystem
 			if (explicitSplit < 0)
 				return false;
 
-			if (!explicitMounts.TryGetValue(filename.Substring(0, explicitSplit), out var explicitPackage))
+			if (!explicitMounts.TryGetValue(filename[..explicitSplit], out var explicitPackage))
 				return false;
 
 			if (installedMods[modID].Package == explicitPackage)
@@ -297,8 +297,8 @@ namespace OpenRA.FileSystem
 			var explicitSplit = path.IndexOf('|');
 			if (explicitSplit > 0 && !path.StartsWith("^"))
 			{
-				var parent = path.Substring(0, explicitSplit);
-				var filename = path.Substring(explicitSplit + 1);
+				var parent = path[..explicitSplit];
+				var filename = path[(explicitSplit + 1)..];
 
 				var parentPath = manifest.Packages.FirstOrDefault(kv => kv.Value == parent).Key;
 				if (parentPath == null)
@@ -306,7 +306,7 @@ namespace OpenRA.FileSystem
 
 				if (parentPath.StartsWith("$", StringComparison.Ordinal))
 				{
-					if (!installedMods.TryGetValue(parentPath.Substring(1), out var mod))
+					if (!installedMods.TryGetValue(parentPath[1..], out var mod))
 						return null;
 
 					if (!(mod.Package is Folder))
@@ -329,7 +329,7 @@ namespace OpenRA.FileSystem
 			if (resolved == null)
 				return null;
 
-			foreach (var name in path.Substring(resolved.Length).Split(Path.DirectorySeparatorChar, Path.AltDirectorySeparatorChar))
+			foreach (var name in path[resolved.Length..].Split(Path.DirectorySeparatorChar, Path.AltDirectorySeparatorChar))
 			{
 				// Filter out paths of the form /foo/bar/./baz
 				if (name == ".")
diff --git a/OpenRA.Game/FileSystem/ZipFile.cs b/OpenRA.Game/FileSystem/ZipFile.cs
index d5ce5471cc..60356b778c 100644
--- a/OpenRA.Game/FileSystem/ZipFile.cs
+++ b/OpenRA.Game/FileSystem/ZipFile.cs
@@ -148,7 +148,7 @@ namespace OpenRA.FileSystem
 			public ZipFolder(ReadOnlyZipFile parent, string path)
 			{
 				if (path.EndsWith("/", StringComparison.Ordinal))
-					path = path.Substring(0, path.Length - 1);
+					path = path[..^1];
 
 				Name = path;
 				Parent = parent;
@@ -168,7 +168,7 @@ namespace OpenRA.FileSystem
 					{
 						if (entry.StartsWith(Name, StringComparison.Ordinal) && entry != Name)
 						{
-							var filename = entry.Substring(Name.Length + 1);
+							var filename = entry[(Name.Length + 1)..];
 							var dirLevels = filename.Split('/').Count(c => !string.IsNullOrEmpty(c));
 							if (dirLevels == 1)
 								yield return filename;
diff --git a/OpenRA.Game/Game.cs b/OpenRA.Game/Game.cs
index 8b8a671a48..0f69d542f7 100644
--- a/OpenRA.Game/Game.cs
+++ b/OpenRA.Game/Game.cs
@@ -416,7 +416,7 @@ namespace OpenRA
 				// Sanitize input from platform-specific launchers
 				// Process.Start requires paths to not be quoted, even if they contain spaces
 				if (launchPath != null && launchPath.First() == '"' && launchPath.Last() == '"')
-					launchPath = launchPath.Substring(1, launchPath.Length - 2);
+					launchPath = launchPath[1..^1];
 
 				// Metadata registration requires an explicit launch path
 				if (launchPath != null)
diff --git a/OpenRA.Game/Input/Hotkey.cs b/OpenRA.Game/Input/Hotkey.cs
index 5b4fe62ad7..995887847e 100644
--- a/OpenRA.Game/Input/Hotkey.cs
+++ b/OpenRA.Game/Input/Hotkey.cs
@@ -42,7 +42,7 @@ namespace OpenRA
 			var mods = Modifiers.None;
 			if (parts.Length >= 2)
 			{
-				var modString = s.Substring(s.IndexOf(' '));
+				var modString = s[s.IndexOf(' ')..];
 				if (!Enum<Modifiers>.TryParse(modString, true, out mods))
 					return false;
 			}
diff --git a/OpenRA.Game/Map/ActorReference.cs b/OpenRA.Game/Map/ActorReference.cs
index eb0259123a..090375ccab 100644
--- a/OpenRA.Game/Map/ActorReference.cs
+++ b/OpenRA.Game/Map/ActorReference.cs
@@ -94,7 +94,7 @@ namespace OpenRA
 					continue;
 
 				var initTypeName = init.GetType().Name;
-				var initName = initTypeName.Substring(0, initTypeName.Length - 4);
+				var initName = initTypeName[..^4];
 				if (!string.IsNullOrEmpty(init.InstanceName))
 					initName += ActorInfo.TraitInstanceSeparator + init.InstanceName;
 
diff --git a/OpenRA.Game/Map/MapCache.cs b/OpenRA.Game/Map/MapCache.cs
index ccbdefd670..064cdfec1d 100644
--- a/OpenRA.Game/Map/MapCache.cs
+++ b/OpenRA.Game/Map/MapCache.cs
@@ -99,7 +99,7 @@ namespace OpenRA
 				IReadOnlyPackage package;
 				var optional = name.StartsWith("~", StringComparison.Ordinal);
 				if (optional)
-					name = name.Substring(1);
+					name = name[1..];
 
 				try
 				{
@@ -183,7 +183,7 @@ namespace OpenRA
 				var name = kv.Key;
 				var optional = name.StartsWith("~", StringComparison.Ordinal);
 				if (optional)
-					name = name.Substring(1);
+					name = name[1..];
 
 				// Don't try to open the map directory in the support directory if it doesn't exist
 				var resolved = Platform.ResolvePath(name);
diff --git a/OpenRA.Game/MiniYaml.cs b/OpenRA.Game/MiniYaml.cs
index 77ec2ea3e2..4bea7e90ed 100644
--- a/OpenRA.Game/MiniYaml.cs
+++ b/OpenRA.Game/MiniYaml.cs
@@ -254,7 +254,7 @@ namespace OpenRA
 					}
 
 					if (commentStart >= 0 && !discardCommentsAndWhitespace)
-						comment = line.Slice(commentStart);
+						comment = line[commentStart..];
 
 					if (value.Length > 1)
 					{
@@ -376,7 +376,7 @@ namespace OpenRA
 				}
 				else if (n.Key.StartsWith("-", StringComparison.Ordinal))
 				{
-					var removed = n.Key.Substring(1);
+					var removed = n.Key[1..];
 					if (resolved.RemoveAll(r => r.Key == removed) == 0)
 						throw new YamlException($"{n.Location}: There are no elements with key `{removed}` to remove");
 				}
diff --git a/OpenRA.Game/Network/UnitOrders.cs b/OpenRA.Game/Network/UnitOrders.cs
index 186b1d1491..33d611fad1 100644
--- a/OpenRA.Game/Network/UnitOrders.cs
+++ b/OpenRA.Game/Network/UnitOrders.cs
@@ -75,7 +75,7 @@ namespace OpenRA.Network
 						// Cut chat messages to the hard limit to avoid exploits
 						var message = order.TargetString;
 						if (message.Length > ChatMessageMaxLength)
-							message = order.TargetString.Substring(0, ChatMessageMaxLength);
+							message = order.TargetString[..ChatMessageMaxLength];
 
 						// ExtraData 0 means this is a normal chat order, everything else is team chat
 						if (order.ExtraData == 0)
diff --git a/OpenRA.Game/Platform.cs b/OpenRA.Game/Platform.cs
index 07b638e0e9..dcfe8afe83 100644
--- a/OpenRA.Game/Platform.cs
+++ b/OpenRA.Game/Platform.cs
@@ -244,13 +244,13 @@ namespace OpenRA
 				return BinDir;
 
 			if (path.StartsWith("^SupportDir|", StringComparison.Ordinal))
-				path = SupportDir + path.Substring(12);
+				path = SupportDir + path[12..];
 
 			if (path.StartsWith("^EngineDir|", StringComparison.Ordinal))
-				path = EngineDir + path.Substring(11);
+				path = EngineDir + path[11..];
 
 			if (path.StartsWith("^BinDir|", StringComparison.Ordinal))
-				path = BinDir + path.Substring(8);
+				path = BinDir + path[8..];
 
 			return path;
 		}
diff --git a/OpenRA.Game/Primitives/Color.cs b/OpenRA.Game/Primitives/Color.cs
index c5210c5670..1d5f79f006 100644
--- a/OpenRA.Game/Primitives/Color.cs
+++ b/OpenRA.Game/Primitives/Color.cs
@@ -168,13 +168,13 @@ namespace OpenRA.Primitives
 				return false;
 
 			byte alpha = 255;
-			if (!byte.TryParse(value.Substring(0, 2), NumberStyles.HexNumber, CultureInfo.InvariantCulture, out var red)
-			    || !byte.TryParse(value.Substring(2, 2), NumberStyles.HexNumber, CultureInfo.InvariantCulture, out var green)
-			    || !byte.TryParse(value.Substring(4, 2), NumberStyles.HexNumber, CultureInfo.InvariantCulture, out var blue))
+			if (!byte.TryParse(value[0..2], NumberStyles.HexNumber, CultureInfo.InvariantCulture, out var red)
+			    || !byte.TryParse(value[2..4], NumberStyles.HexNumber, CultureInfo.InvariantCulture, out var green)
+			    || !byte.TryParse(value[4..6], NumberStyles.HexNumber, CultureInfo.InvariantCulture, out var blue))
 				return false;
 
 			if (value.Length == 8
-			    && !byte.TryParse(value.Substring(6, 2), NumberStyles.HexNumber, CultureInfo.InvariantCulture, out alpha))
+			    && !byte.TryParse(value[6..8], NumberStyles.HexNumber, CultureInfo.InvariantCulture, out alpha))
 				return false;
 
 			color = FromArgb(alpha, red, green, blue);
diff --git a/OpenRA.Game/Settings.cs b/OpenRA.Game/Settings.cs
index 008a00a677..87948fea30 100644
--- a/OpenRA.Game/Settings.cs
+++ b/OpenRA.Game/Settings.cs
@@ -443,7 +443,7 @@ namespace OpenRA
 
 			// avoid UI glitches
 			if (clean.Length > 16)
-				clean = clean.Substring(0, 16);
+				clean = clean[..16];
 
 			return clean;
 		}
diff --git a/OpenRA.Game/Support/VariableExpression.cs b/OpenRA.Game/Support/VariableExpression.cs
index 2906f6a420..77db5a97ea 100644
--- a/OpenRA.Game/Support/VariableExpression.cs
+++ b/OpenRA.Game/Support/VariableExpression.cs
@@ -354,7 +354,7 @@ namespace OpenRA.Support
 						if (cc != CharClass.Digit)
 						{
 							if (cc != CharClass.Whitespace && cc != CharClass.Operator && cc != CharClass.Mixed)
-								throw new InvalidDataException($"Number {int.Parse(expression.Substring(start, i - start))} and variable merged at index {start}");
+								throw new InvalidDataException($"Number {int.Parse(expression[start..i])} and variable merged at index {start}");
 
 							return true;
 						}
@@ -369,7 +369,7 @@ namespace OpenRA.Support
 			static TokenType VariableOrKeyword(string expression, int start, ref int i)
 			{
 				if (CharClassOf(expression[i - 1]) == CharClass.Mixed)
-					throw new InvalidDataException($"Invalid identifier end character at index {i - 1} for `{expression.Substring(start, i - start)}`");
+					throw new InvalidDataException($"Invalid identifier end character at index {i - 1} for `{expression[start..i]}`");
 
 				return VariableOrKeyword(expression, start, i - start);
 			}
@@ -540,10 +540,10 @@ namespace OpenRA.Support
 				switch (type)
 				{
 					case TokenType.Number:
-						return new NumberToken(start, expression.Substring(start, i - start));
+						return new NumberToken(start, expression[start..i]);
 
 					case TokenType.Variable:
-						return new VariableToken(start, expression.Substring(start, i - start));
+						return new VariableToken(start, expression[start..i]);
 
 					default:
 						return new Token(type, start);
diff --git a/OpenRA.Game/Widgets/WidgetLoader.cs b/OpenRA.Game/Widgets/WidgetLoader.cs
index d0938ceb44..3222b3e76d 100644
--- a/OpenRA.Game/Widgets/WidgetLoader.cs
+++ b/OpenRA.Game/Widgets/WidgetLoader.cs
@@ -28,7 +28,7 @@ namespace OpenRA
 			foreach (var file in modData.Manifest.ChromeLayout.Select(a => MiniYaml.FromStream(modData.DefaultFileSystem.Open(a), a)))
 				foreach (var w in file)
 				{
-					var key = w.Key.Substring(w.Key.IndexOf('@') + 1);
+					var key = w.Key[(w.Key.IndexOf('@') + 1)..];
 					if (widgets.ContainsKey(key))
 						throw new InvalidDataException($"Widget has duplicate Key `{w.Key}` at {w.Location}");
 					widgets.Add(key, w);
diff --git a/OpenRA.Mods.Cnc/FileFormats/IdxEntry.cs b/OpenRA.Mods.Cnc/FileFormats/IdxEntry.cs
index e5a95f841c..ae7fac664c 100644
--- a/OpenRA.Mods.Cnc/FileFormats/IdxEntry.cs
+++ b/OpenRA.Mods.Cnc/FileFormats/IdxEntry.cs
@@ -27,7 +27,7 @@ namespace OpenRA.Mods.Cnc.FileFormats
 			var name = s.ReadASCII(16);
 			var pos = name.IndexOf('\0');
 			if (pos != 0)
-				name = name.Substring(0, pos);
+				name = name[..pos];
 
 			Filename = string.Concat(name, ".wav");
 			Offset = s.ReadUInt32();
diff --git a/OpenRA.Mods.Cnc/UtilityCommands/Glob.cs b/OpenRA.Mods.Cnc/UtilityCommands/Glob.cs
index b11fe898f0..79821d2d5c 100644
--- a/OpenRA.Mods.Cnc/UtilityCommands/Glob.cs
+++ b/OpenRA.Mods.Cnc/UtilityCommands/Glob.cs
@@ -46,11 +46,11 @@ namespace OpenRA.Mods.Cnc.UtilityCommands
 				var index = filePath.IndexOfAny(DirectorySeparators, startIndex);
 				if (index == -1)
 				{
-					parts.Add(filePath.Substring(startIndex));
+					parts.Add(filePath[startIndex..]);
 					break;
 				}
 
-				parts.Add(filePath.Substring(startIndex, index - startIndex + 1));
+				parts.Add(filePath[startIndex..index]);
 				startIndex = index + 1;
 			}
 
@@ -106,7 +106,7 @@ namespace OpenRA.Mods.Cnc.UtilityCommands
 				else
 				{
 					if (dir[^1] == Path.DirectorySeparatorChar || dir[^1] == Path.AltDirectorySeparatorChar)
-						dir = dir.Substring(0, dir.Length - 1);
+						dir = dir[..^1];
 					foreach (var subDir in Directory.EnumerateDirectories(basePath, dir, SearchOption.TopDirectoryOnly))
 						foreach (var s in Expand(subDir, dirs, dirIndex + 1, file))
 							yield return s;
diff --git a/OpenRA.Mods.Cnc/UtilityCommands/ImportTiberianDawnLegacyMapCommand.cs b/OpenRA.Mods.Cnc/UtilityCommands/ImportTiberianDawnLegacyMapCommand.cs
index 954e262271..eb77730ad0 100644
--- a/OpenRA.Mods.Cnc/UtilityCommands/ImportTiberianDawnLegacyMapCommand.cs
+++ b/OpenRA.Mods.Cnc/UtilityCommands/ImportTiberianDawnLegacyMapCommand.cs
@@ -165,7 +165,7 @@ namespace OpenRA.Mods.Cnc.UtilityCommands
 
 		public override void ReadPacks(IniFile file, string filename)
 		{
-			using (var s = File.OpenRead(filename.Substring(0, filename.Length - 4) + ".bin"))
+			using (var s = File.OpenRead(filename[..^4] + ".bin"))
 				UnpackTileData(s);
 
 			ReadOverlay(file);
diff --git a/OpenRA.Mods.Common/Commands/ChatCommands.cs b/OpenRA.Mods.Common/Commands/ChatCommands.cs
index f18f72303d..53b68a018a 100644
--- a/OpenRA.Mods.Common/Commands/ChatCommands.cs
+++ b/OpenRA.Mods.Common/Commands/ChatCommands.cs
@@ -36,11 +36,11 @@ namespace OpenRA.Mods.Common.Commands
 		{
 			if (message.StartsWith("/"))
 			{
-				var name = message.Substring(1).Split(' ')[0].ToLowerInvariant();
+				var name = message[1..].Split(' ')[0].ToLowerInvariant();
 				var command = Commands.FirstOrDefault(x => x.Key == name);
 
 				if (command.Value != null)
-					command.Value.InvokeCommand(name.ToLowerInvariant(), message.Substring(1 + name.Length).Trim());
+					command.Value.InvokeCommand(name.ToLowerInvariant(), message[(1 + name.Length)..].Trim());
 				else
 					TextNotificationsManager.Debug(Game.ModData.Translation.GetString(InvalidCommand, Translation.Arguments("name", name)));
 
diff --git a/OpenRA.Mods.Common/FileFormats/IniFile.cs b/OpenRA.Mods.Common/FileFormats/IniFile.cs
index 9a2b0838ae..b854479826 100644
--- a/OpenRA.Mods.Common/FileFormats/IniFile.cs
+++ b/OpenRA.Mods.Common/FileFormats/IniFile.cs
@@ -67,7 +67,7 @@ namespace OpenRA.Mods.Common.FileFormats
 		{
 			var comment = line.IndexOf(';');
 			if (comment >= 0)
-				line = line.Substring(0, comment);
+				line = line[..comment];
 
 			line = line.Trim();
 			if (line.Length == 0)
@@ -78,8 +78,8 @@ namespace OpenRA.Mods.Common.FileFormats
 			var eq = line.IndexOf('=');
 			if (eq >= 0)
 			{
-				key = line.Substring(0, eq).Trim();
-				value = line.Substring(eq + 1, line.Length - eq - 1).Trim();
+				key = line[..eq].Trim();
+				value = line[(eq + 1)..].Trim();
 			}
 
 			if (currentSection == null)
diff --git a/OpenRA.Mods.Common/Lint/CheckChromeHotkeys.cs b/OpenRA.Mods.Common/Lint/CheckChromeHotkeys.cs
index da16b070d0..8f72eac535 100644
--- a/OpenRA.Mods.Common/Lint/CheckChromeHotkeys.cs
+++ b/OpenRA.Mods.Common/Lint/CheckChromeHotkeys.cs
@@ -40,7 +40,7 @@ namespace OpenRA.Mods.Common.Lint
 			var checkWidgetFields = modData.ObjectCreator.GetTypesImplementing<Widget>()
 				.SelectMany(w => Utility.GetFields(w)
 					.Where(f => f.FieldType == typeof(HotkeyReference))
-					.Select(f => (w.Name.Substring(0, w.Name.Length - 6), f.Name)))
+					.Select(f => (w.Name[..^6], f.Name)))
 				.ToArray();
 
 			var customLintMethods = new Dictionary<string, List<string>>();
@@ -52,7 +52,7 @@ namespace OpenRA.Mods.Common.Lint
 					var p = m.GetParameters();
 					if (p.Length == 3 && p[0].ParameterType == typeof(MiniYamlNode) && p[1].ParameterType == typeof(Action<string>)
 							&& p[2].ParameterType == typeof(Action<string>))
-						customLintMethods.GetOrAdd(w.Name.Substring(0, w.Name.Length - 6)).Add(m.Name);
+						customLintMethods.GetOrAdd(w.Name[..^6]).Add(m.Name);
 				}
 			}
 
diff --git a/OpenRA.Mods.Common/Lint/CheckUnknownTraitFields.cs b/OpenRA.Mods.Common/Lint/CheckUnknownTraitFields.cs
index 57171dbe38..271ca97777 100644
--- a/OpenRA.Mods.Common/Lint/CheckUnknownTraitFields.cs
+++ b/OpenRA.Mods.Common/Lint/CheckUnknownTraitFields.cs
@@ -38,7 +38,7 @@ namespace OpenRA.Mods.Common.Lint
 		{
 			var name = key.Split('@')[0];
 			if (name.StartsWith("-", StringComparison.Ordinal))
-				return name.Substring(1);
+				return name[1..];
 
 			return name;
 		}
diff --git a/OpenRA.Mods.Common/Lint/CheckUnknownWeaponFields.cs b/OpenRA.Mods.Common/Lint/CheckUnknownWeaponFields.cs
index a8ec77aaee..f0569d4ead 100644
--- a/OpenRA.Mods.Common/Lint/CheckUnknownWeaponFields.cs
+++ b/OpenRA.Mods.Common/Lint/CheckUnknownWeaponFields.cs
@@ -39,7 +39,7 @@ namespace OpenRA.Mods.Common.Lint
 		{
 			var name = key.Split('@')[0];
 			if (name.StartsWith("-", StringComparison.Ordinal))
-				return name.Substring(1);
+				return name[1..];
 
 			return name;
 		}
diff --git a/OpenRA.Mods.Common/Traits/Render/ProductionIconOverlayManager.cs b/OpenRA.Mods.Common/Traits/Render/ProductionIconOverlayManager.cs
index 78e9f1e3fb..76ecbd9f3a 100644
--- a/OpenRA.Mods.Common/Traits/Render/ProductionIconOverlayManager.cs
+++ b/OpenRA.Mods.Common/Traits/Render/ProductionIconOverlayManager.cs
@@ -104,7 +104,7 @@ namespace OpenRA.Mods.Common.Traits.Render
 
 		string GetName(string key)
 		{
-			return key.Substring(prefix.Length);
+			return key[prefix.Length..];
 		}
 
 		public void PrerequisitesAvailable(string key)
diff --git a/OpenRA.Mods.Common/Traits/Render/RenderSprites.cs b/OpenRA.Mods.Common/Traits/Render/RenderSprites.cs
index 4e31c4acd5..8eab8427f0 100644
--- a/OpenRA.Mods.Common/Traits/Render/RenderSprites.cs
+++ b/OpenRA.Mods.Common/Traits/Render/RenderSprites.cs
@@ -240,7 +240,7 @@ namespace OpenRA.Mods.Common.Traits.Render
 			{
 				if (sequence.StartsWith(s.Prefix, StringComparison.Ordinal))
 				{
-					sequence = sequence.Substring(s.Prefix.Length);
+					sequence = sequence[s.Prefix.Length..];
 					break;
 				}
 			}
diff --git a/OpenRA.Mods.Common/Traits/Render/WithNameTagDecoration.cs b/OpenRA.Mods.Common/Traits/Render/WithNameTagDecoration.cs
index d47e089a4e..6030709470 100644
--- a/OpenRA.Mods.Common/Traits/Render/WithNameTagDecoration.cs
+++ b/OpenRA.Mods.Common/Traits/Render/WithNameTagDecoration.cs
@@ -56,7 +56,7 @@ namespace OpenRA.Mods.Common.Traits.Render
 
 			name = self.Owner.PlayerName;
 			if (name.Length > info.MaxLength)
-				name = name.Substring(0, info.MaxLength);
+				name = name[..info.MaxLength];
 		}
 
 		protected override IEnumerable<IRenderable> RenderDecoration(Actor self, WorldRenderer wr, int2 screenPos)
@@ -78,7 +78,7 @@ namespace OpenRA.Mods.Common.Traits.Render
 
 			name = self.Owner.PlayerName;
 			if (name.Length > Info.MaxLength)
-				name = name.Substring(0, Info.MaxLength);
+				name = name[..Info.MaxLength];
 		}
 	}
 }
diff --git a/OpenRA.Mods.Common/Traits/World/EditorActorLayer.cs b/OpenRA.Mods.Common/Traits/World/EditorActorLayer.cs
index af3e7c9a84..184a34d48d 100644
--- a/OpenRA.Mods.Common/Traits/World/EditorActorLayer.cs
+++ b/OpenRA.Mods.Common/Traits/World/EditorActorLayer.cs
@@ -201,7 +201,7 @@ namespace OpenRA.Mods.Common.Traits
 			foreach (var kv in mp)
 			{
 				var name = kv.Key;
-				var index = int.Parse(name.Substring(5));
+				var index = int.Parse(name[5..]);
 
 				if (index >= newCount)
 				{
diff --git a/OpenRA.Mods.Common/UpdateRules/Rules/20221203/ExplicitSequenceFilenames.cs b/OpenRA.Mods.Common/UpdateRules/Rules/20221203/ExplicitSequenceFilenames.cs
index c07286d0e5..1fbb8d94af 100644
--- a/OpenRA.Mods.Common/UpdateRules/Rules/20221203/ExplicitSequenceFilenames.cs
+++ b/OpenRA.Mods.Common/UpdateRules/Rules/20221203/ExplicitSequenceFilenames.cs
@@ -359,7 +359,7 @@ namespace OpenRA.Mods.Common.UpdateRules.Rules
 			// Replace removals with masking
 			foreach (var node in sequenceNode.Value.Nodes)
 				if (node.Key?.StartsWith("-") ?? false)
-					node.Key = node.Key.Substring(1);
+					node.Key = node.Key[1..];
 
 			var combineNode = sequenceNode.LastChildMatching("Combine");
 			if (combineNode != null)
@@ -389,8 +389,8 @@ namespace OpenRA.Mods.Common.UpdateRules.Rules
 
 					var overrideFilename = filename;
 					if (useTilesetCode)
-						overrideFilename = filename.Substring(0, 1) + tilesetCodes[sequenceTileset] +
-						                   filename.Substring(2, filename.Length - 2);
+						overrideFilename = filename[..1] + tilesetCodes[sequenceTileset] +
+						                   filename[2..];
 
 					if (addExtension)
 						overrideFilename += useTilesetExtension ? tilesetExtensions[sequenceTileset] : defaultSpriteExtension;
diff --git a/OpenRA.Mods.Common/UpdateRules/UpdateUtils.cs b/OpenRA.Mods.Common/UpdateRules/UpdateUtils.cs
index ae1a7ec6a9..ed520cf127 100644
--- a/OpenRA.Mods.Common/UpdateRules/UpdateUtils.cs
+++ b/OpenRA.Mods.Common/UpdateRules/UpdateUtils.cs
@@ -327,7 +327,7 @@ namespace OpenRA.Mods.Common.UpdateRules
 			var prefix = includeRemovals && node.IsRemoval() ? "-" : "";
 			var split = node.Key.IndexOf("@", StringComparison.Ordinal);
 			if (preserveSuffix && split > -1)
-				node.Key = prefix + newKey + node.Key.Substring(split);
+				node.Key = prefix + newKey + node.Key[split..];
 			else
 				node.Key = prefix + newKey;
 		}
@@ -391,7 +391,7 @@ namespace OpenRA.Mods.Common.UpdateRules
 				return false;
 
 			var atPosition = node.Key.IndexOf('@');
-			return atPosition > 0 && node.Key.Substring(0, atPosition) == prefix + match;
+			return atPosition > 0 && node.Key[..atPosition] == prefix + match;
 		}
 
 		/// <summary>Returns true if the node is of the form [match], [match]@[arbitrary suffix] or [arbitrary suffix]@[match].</summary>
@@ -401,7 +401,7 @@ namespace OpenRA.Mods.Common.UpdateRules
 				return false;
 
 			var atPosition = node.Key.IndexOf('@');
-			var relevantPart = ignoreSuffix && atPosition > 0 ? node.Key.Substring(0, atPosition) : node.Key;
+			var relevantPart = ignoreSuffix && atPosition > 0 ? node.Key[..atPosition] : node.Key;
 
 			if (relevantPart.Contains(match) && (includeRemovals || !node.IsRemoval()))
 				return true;
diff --git a/OpenRA.Mods.Common/Util.cs b/OpenRA.Mods.Common/Util.cs
index 6f98d43f43..93abb794c1 100644
--- a/OpenRA.Mods.Common/Util.cs
+++ b/OpenRA.Mods.Common/Util.cs
@@ -229,7 +229,7 @@ namespace OpenRA.Mods.Common
 		public static string InternalTypeName(Type t)
 		{
 			return t.IsGenericType
-				? $"{t.Name.Substring(0, t.Name.IndexOf('`'))}<{string.Join(", ", t.GenericTypeArguments.Select(arg => arg.Name))}>"
+				? $"{t.Name[..t.Name.IndexOf('`')]}<{string.Join(", ", t.GenericTypeArguments.Select(arg => arg.Name))}>"
 				: t.Name;
 		}
 
diff --git a/OpenRA.Mods.Common/UtilityCommands/ExtractEmmyLuaAPI.cs b/OpenRA.Mods.Common/UtilityCommands/ExtractEmmyLuaAPI.cs
index 6473838b76..61ad1e1be5 100644
--- a/OpenRA.Mods.Common/UtilityCommands/ExtractEmmyLuaAPI.cs
+++ b/OpenRA.Mods.Common/UtilityCommands/ExtractEmmyLuaAPI.cs
@@ -129,7 +129,7 @@ namespace OpenRA.Mods.Common.UtilityCommands
 			var localEnums = new List<Type>();
 			foreach (var init in actorInits)
 			{
-				var name = init.Name.Substring(0, init.Name.Length - 4);
+				var name = init.Name[..^4];
 				var parameters = init.GetConstructors().Select(ci => ci.GetParameters());
 				var parameterString = string.Join(" | ",
 					parameters
diff --git a/OpenRA.Mods.Common/UtilityCommands/ExtractTraitDocsCommand.cs b/OpenRA.Mods.Common/UtilityCommands/ExtractTraitDocsCommand.cs
index c8d130e1d0..bf412a7108 100644
--- a/OpenRA.Mods.Common/UtilityCommands/ExtractTraitDocsCommand.cs
+++ b/OpenRA.Mods.Common/UtilityCommands/ExtractTraitDocsCommand.cs
@@ -53,7 +53,7 @@ namespace OpenRA.Mods.Common.UtilityCommands
 				.Select(type => new
 				{
 					type.Namespace,
-					Name = type.Name.EndsWith("Info") ? type.Name.Substring(0, type.Name.Length - 4) : type.Name,
+					Name = type.Name.EndsWith("Info") ? type.Name[..^4] : type.Name,
 					Description = string.Join(" ", Utility.GetCustomAttributes<DescAttribute>(type, false).SelectMany(d => d.Lines)),
 					RequiresTraits = RequiredTraitTypes(type)
 						.Select(y => y.Name),
@@ -79,7 +79,7 @@ namespace OpenRA.Mods.Common.UtilityCommands
 									.Select(a =>
 									{
 										var name = a.AttributeType.Name;
-										name = name.EndsWith("Attribute") ? name.Substring(0, name.Length - 9) : name;
+										name = name.EndsWith("Attribute") ? name[..^9] : name;
 
 										return new
 										{
diff --git a/OpenRA.Mods.Common/UtilityCommands/ExtractWeaponDocsCommand.cs b/OpenRA.Mods.Common/UtilityCommands/ExtractWeaponDocsCommand.cs
index a2a432ba3e..389b5fe9a7 100644
--- a/OpenRA.Mods.Common/UtilityCommands/ExtractWeaponDocsCommand.cs
+++ b/OpenRA.Mods.Common/UtilityCommands/ExtractWeaponDocsCommand.cs
@@ -58,7 +58,7 @@ namespace OpenRA.Mods.Common.UtilityCommands
 				.Select(type => new
 				{
 					type.Namespace,
-					Name = type.Name.EndsWith("Info") ? type.Name.Substring(0, type.Name.Length - 4) : type.Name,
+					Name = type.Name.EndsWith("Info") ? type.Name[..^4] : type.Name,
 					Description = string.Join(" ", Utility.GetCustomAttributes<DescAttribute>(type, false).SelectMany(d => d.Lines)),
 					InheritedTypes = type.BaseTypes()
 						.Select(y => y.Name)
@@ -82,7 +82,7 @@ namespace OpenRA.Mods.Common.UtilityCommands
 									.Select(a =>
 									{
 										var name = a.AttributeType.Name;
-										name = name.EndsWith("Attribute") ? name.Substring(0, name.Length - 9) : name;
+										name = name.EndsWith("Attribute") ? name[..^9] : name;
 
 										return new
 										{
diff --git a/OpenRA.Mods.Common/UtilityCommands/ImportLegacyMapCommand.cs b/OpenRA.Mods.Common/UtilityCommands/ImportLegacyMapCommand.cs
index 48509f067b..671c528efb 100644
--- a/OpenRA.Mods.Common/UtilityCommands/ImportLegacyMapCommand.cs
+++ b/OpenRA.Mods.Common/UtilityCommands/ImportLegacyMapCommand.cs
@@ -231,7 +231,7 @@ namespace OpenRA.Mods.Common.UtilityCommands
 
 		static string Truncate(string s, int maxLength)
 		{
-			return s.Length <= maxLength ? s : s.Substring(0, maxLength);
+			return s.Length <= maxLength ? s : s[..maxLength];
 		}
 
 		static string GetTileset(IniSection mapSection)
diff --git a/OpenRA.Mods.Common/Widgets/LabelWithHighlightWidget.cs b/OpenRA.Mods.Common/Widgets/LabelWithHighlightWidget.cs
index 3826b83825..2c7f506cbb 100644
--- a/OpenRA.Mods.Common/Widgets/LabelWithHighlightWidget.cs
+++ b/OpenRA.Mods.Common/Widgets/LabelWithHighlightWidget.cs
@@ -51,13 +51,13 @@ namespace OpenRA.Mods.Common.Widgets
 					if (highlightStart > 0 && highlightEnd > highlightStart)
 					{
 						// Normal line segment before highlight
-						var lineNormal = line.Substring(0, highlightStart);
+						var lineNormal = line[..highlightStart];
 						components.Add((lineNormal, false));
 
 						// Highlight line segment
-						var lineHighlight = line.Substring(highlightStart + 1, highlightEnd - highlightStart - 1);
+						var lineHighlight = line[(highlightStart + 1)..highlightEnd];
 						components.Add((lineHighlight, true));
-						line = line.Substring(highlightEnd + 1);
+						line = line[(highlightEnd + 1)..];
 					}
 					else
 					{
diff --git a/OpenRA.Mods.Common/Widgets/Logic/AssetBrowserLogic.cs b/OpenRA.Mods.Common/Widgets/Logic/AssetBrowserLogic.cs
index 37d23f54c0..ba15b1d315 100644
--- a/OpenRA.Mods.Common/Widgets/Logic/AssetBrowserLogic.cs
+++ b/OpenRA.Mods.Common/Widgets/Logic/AssetBrowserLogic.cs
@@ -676,15 +676,15 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 				name = source.Name;
 				var compare = Platform.CurrentPlatform == PlatformType.Windows ? StringComparison.OrdinalIgnoreCase : StringComparison.Ordinal;
 				if (name.StartsWith(modData.Manifest.Package.Name, compare))
-					name = "$" + modData.Manifest.Id + "/" + name.Substring(modData.Manifest.Package.Name.Length + 1);
+					name = "$" + modData.Manifest.Id + "/" + name[(modData.Manifest.Package.Name.Length + 1)..];
 				else if (name.StartsWith(Platform.EngineDir, compare))
-					name = "./" + name.Substring(Platform.EngineDir.Length);
+					name = "./" + name[Platform.EngineDir.Length..];
 				else if (name.StartsWith(Platform.SupportDir, compare))
-					name = "^" + name.Substring(Platform.SupportDir.Length);
+					name = "^" + name[Platform.SupportDir.Length..];
 			}
 
 			if (name.Length > 18)
-				name = "..." + name.Substring(name.Length - 15);
+				name = "..." + name[^15..];
 
 			return name;
 		}
diff --git a/OpenRA.Mods.Common/Widgets/Logic/DirectConnectLogic.cs b/OpenRA.Mods.Common/Widgets/Logic/DirectConnectLogic.cs
index 62b8ac2c33..0fec9f8e10 100644
--- a/OpenRA.Mods.Common/Widgets/Logic/DirectConnectLogic.cs
+++ b/OpenRA.Mods.Common/Widgets/Logic/DirectConnectLogic.cs
@@ -35,8 +35,8 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 			}
 			else
 			{
-				ipField.Text = text.Substring(0, last);
-				portField.Text = text.Substring(last + 1);
+				ipField.Text = text[..last];
+				portField.Text = text[(last + 1)..];
 			}
 
 			var joinButton = panel.Get<ButtonWidget>("JOIN_BUTTON");
diff --git a/OpenRA.Mods.Common/Widgets/Logic/Lobby/LobbyUtils.cs b/OpenRA.Mods.Common/Widgets/Logic/Lobby/LobbyUtils.cs
index 02ac98670e..06cb6b9fa8 100644
--- a/OpenRA.Mods.Common/Widgets/Logic/Lobby/LobbyUtils.cs
+++ b/OpenRA.Mods.Common/Widgets/Logic/Lobby/LobbyUtils.cs
@@ -205,8 +205,8 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 				return (null, null);
 
 			var split = input.IndexOf(token, StringComparison.Ordinal);
-			var first = split > 0 ? input.Substring(0, split) : input;
-			var second = split > 0 ? input.Substring(split + token.Length) : null;
+			var first = split > 0 ? input[..split] : input;
+			var second = split > 0 ? input[(split + token.Length)..] : null;
 			return (first, second);
 		}
 
diff --git a/OpenRA.Mods.Common/Widgets/Logic/TabCompletionLogic.cs b/OpenRA.Mods.Common/Widgets/Logic/TabCompletionLogic.cs
index 3169f96268..93d1bdcd91 100644
--- a/OpenRA.Mods.Common/Widgets/Logic/TabCompletionLogic.cs
+++ b/OpenRA.Mods.Common/Widgets/Logic/TabCompletionLogic.cs
@@ -44,7 +44,7 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 			{
 				prefix = "/";
 				suffix = "";
-				toComplete = text.Substring(1);
+				toComplete = text[1..];
 				candidates = Commands.Where(x => x.StartsWith(toComplete, StringComparison.InvariantCultureIgnoreCase)).ToList();
 			}
 			else if (Names != null)
@@ -52,9 +52,9 @@ namespace OpenRA.Mods.Common.Widgets.Logic
 				var oneWord = text.Contains(' ');
 				if (oneWord)
 				{
-					prefix = text.Substring(0, text.LastIndexOf(' ') + 1);
+					prefix = text[..(text.LastIndexOf(' ') + 1)];
 					suffix = "";
-					toComplete = text.Substring(prefix.Length);
+					toComplete = text[prefix.Length..];
 				}
 				else
 				{
diff --git a/OpenRA.Mods.Common/Widgets/TextFieldWidget.cs b/OpenRA.Mods.Common/Widgets/TextFieldWidget.cs
index 033d62207f..5bc54bb3cf 100644
--- a/OpenRA.Mods.Common/Widgets/TextFieldWidget.cs
+++ b/OpenRA.Mods.Common/Widgets/TextFieldWidget.cs
@@ -156,7 +156,7 @@ namespace OpenRA.Mods.Common.Widgets
 			var minValue = int.MaxValue;
 			for (var i = 0; i <= apparentText.Length; i++)
 			{
-				var dist = Math.Abs(start + font.Measure(apparentText.Substring(0, i)).X - x);
+				var dist = Math.Abs(start + font.Measure(apparentText[..i]).X - x);
 				if (dist > minValue)
 					break;
 				minValue = dist;
@@ -168,12 +168,12 @@ namespace OpenRA.Mods.Common.Widgets
 
 		int GetPrevWhitespaceIndex()
 		{
-			return Text.Substring(0, CursorPosition).TrimEnd().LastIndexOf(' ') + 1;
+			return Text[..CursorPosition].TrimEnd().LastIndexOf(' ') + 1;
 		}
 
 		int GetNextWhitespaceIndex()
 		{
-			var substr = Text.Substring(CursorPosition);
+			var substr = Text[CursorPosition..];
 			var substrTrimmed = substr.TrimStart();
 			var trimmedSpaces = substr.Length - substrTrimmed.Length;
 			var nextWhitespace = substrTrimmed.IndexOf(' ');
@@ -335,7 +335,7 @@ namespace OpenRA.Mods.Common.Widgets
 					if (!isOSX && e.Modifiers.HasModifier(Modifiers.Ctrl) && CursorPosition > 0)
 					{
 						// Write directly to the Text backing field to avoid unnecessary validation
-						text = text.Substring(CursorPosition);
+						text = text[CursorPosition..];
 						CursorPosition = 0;
 						ClearSelection();
 						OnTextEdited();
@@ -350,7 +350,7 @@ namespace OpenRA.Mods.Common.Widgets
 					{
 						var lowestIndex = selectionStartIndex < selectionEndIndex ? selectionStartIndex : selectionEndIndex;
 						var highestIndex = selectionStartIndex < selectionEndIndex ? selectionEndIndex : selectionStartIndex;
-						Game.Renderer.SetClipboardText(Text.Substring(lowestIndex, highestIndex - lowestIndex));
+						Game.Renderer.SetClipboardText(Text[lowestIndex..highestIndex]);
 
 						RemoveSelectedText();
 					}
@@ -363,7 +363,7 @@ namespace OpenRA.Mods.Common.Widgets
 					{
 						var lowestIndex = selectionStartIndex < selectionEndIndex ? selectionStartIndex : selectionEndIndex;
 						var highestIndex = selectionStartIndex < selectionEndIndex ? selectionEndIndex : selectionStartIndex;
-						Game.Renderer.SetClipboardText(Text.Substring(lowestIndex, highestIndex - lowestIndex));
+						Game.Renderer.SetClipboardText(Text[lowestIndex..highestIndex]);
 					}
 
 					break;
@@ -377,7 +377,7 @@ namespace OpenRA.Mods.Common.Widgets
 					{
 						// Write directly to the Text backing field to avoid unnecessary validation
 						if ((!isOSX && e.Modifiers.HasModifier(Modifiers.Ctrl)) || (isOSX && e.Modifiers.HasModifier(Modifiers.Alt)))
-							text = text.Substring(0, CursorPosition) + text.Substring(GetNextWhitespaceIndex());
+							text = text[..CursorPosition] + text[GetNextWhitespaceIndex()..];
 						else if (isOSX && e.Modifiers.HasModifier(Modifiers.Meta))
 							text = text.Remove(CursorPosition);
 						else
@@ -400,12 +400,12 @@ namespace OpenRA.Mods.Common.Widgets
 						if ((!isOSX && e.Modifiers.HasModifier(Modifiers.Ctrl)) || (isOSX && e.Modifiers.HasModifier(Modifiers.Alt)))
 						{
 							var prevWhitespace = GetPrevWhitespaceIndex();
-							text = text.Substring(0, prevWhitespace) + text.Substring(CursorPosition);
+							text = text[..prevWhitespace] + text[CursorPosition..];
 							CursorPosition = prevWhitespace;
 						}
 						else if (isOSX && e.Modifiers.HasModifier(Modifiers.Meta))
 						{
-							text = text.Substring(CursorPosition);
+							text = text[CursorPosition..];
 							CursorPosition = 0;
 						}
 						else
@@ -432,7 +432,7 @@ namespace OpenRA.Mods.Common.Widgets
 						// Take only the first line of the clipboard contents
 						var nl = clipboardText.IndexOf('\n');
 						if (nl > 0)
-							clipboardText = clipboardText.Substring(0, nl);
+							clipboardText = clipboardText[..nl];
 
 						clipboardText = clipboardText.Trim();
 						if (clipboardText.Length > 0)
@@ -479,7 +479,7 @@ namespace OpenRA.Mods.Common.Widgets
 				pasteLength = Math.Min(input.Length, MaxLength - Text.Length);
 
 			// Write directly to the Text backing field to avoid repeating the invalid character validation
-			text = text.Insert(CursorPosition, input.Substring(0, pasteLength));
+			text = text.Insert(CursorPosition, input[..pasteLength]);
 			CursorPosition += pasteLength;
 			ClearSelection();
 			OnTextEdited();
@@ -551,7 +551,7 @@ namespace OpenRA.Mods.Common.Widgets
 			var pos = RenderOrigin;
 
 			var textSize = font.Measure(apparentText);
-			var cursorPosition = font.Measure(apparentText.Substring(0, CursorPosition));
+			var cursorPosition = font.Measure(apparentText[..CursorPosition]);
 
 			var disabled = IsDisabled();
 			var hover = Ui.MouseOverWidget == this || Children.Any(c => c == Ui.MouseOverWidget);
@@ -580,8 +580,8 @@ namespace OpenRA.Mods.Common.Widgets
 			{
 				var visualSelectionStartIndex = selectionStartIndex < selectionEndIndex ? selectionStartIndex : selectionEndIndex;
 				var visualSelectionEndIndex = selectionStartIndex < selectionEndIndex ? selectionEndIndex : selectionStartIndex;
-				var highlightStartX = font.Measure(apparentText.Substring(0, visualSelectionStartIndex)).X;
-				var highlightEndX = font.Measure(apparentText.Substring(0, visualSelectionEndIndex)).X;
+				var highlightStartX = font.Measure(apparentText[..visualSelectionStartIndex]).X;
+				var highlightEndX = font.Measure(apparentText[..visualSelectionEndIndex]).X;
 
 				WidgetUtils.FillRectWithColor(
 					new Rectangle(textPos.X + highlightStartX, textPos.Y, highlightEndX - highlightStartX, Bounds.Height - verticalMargin * 2), TextColorHighlight);
diff --git a/OpenRA.Mods.Common/Widgets/WidgetUtils.cs b/OpenRA.Mods.Common/Widgets/WidgetUtils.cs
index c9bcdda992..4cd449df5c 100644
--- a/OpenRA.Mods.Common/Widgets/WidgetUtils.cs
+++ b/OpenRA.Mods.Common/Widgets/WidgetUtils.cs
@@ -249,7 +249,7 @@ namespace OpenRA.Mods.Common.Widgets
 						if (spaceIndex == -1)
 							break;
 
-						var fragmentWidth = font.Measure(line.Substring(0, spaceIndex)).X;
+						var fragmentWidth = font.Measure(line[..spaceIndex]).X;
 						if (fragmentWidth > width)
 							break;
 
@@ -258,8 +258,8 @@ namespace OpenRA.Mods.Common.Widgets
 
 					if (start > 0)
 					{
-						lines[i] = line.Substring(0, start - 1);
-						lines.Insert(i + 1, line.Substring(start));
+						lines[i] = line[..(start - 1)];
+						lines.Insert(i + 1, line[start..]);
 					}
 				}
 
@@ -278,7 +278,7 @@ namespace OpenRA.Mods.Common.Widgets
 			var trimmed = text;
 			while (trimmedWidth > width && trimmed.Length > 3)
 			{
-				trimmed = text.Substring(0, trimmed.Length - 4) + "...";
+				trimmed = text[..(trimmed.Length - 4)] + "...";
 				trimmedWidth = font.Measure(trimmed).X;
 			}
 
diff --git a/OpenRA.Platforms.Default/Sdl2PlatformWindow.cs b/OpenRA.Platforms.Default/Sdl2PlatformWindow.cs
index 848540af3d..b2ebba61ce 100644
--- a/OpenRA.Platforms.Default/Sdl2PlatformWindow.cs
+++ b/OpenRA.Platforms.Default/Sdl2PlatformWindow.cs
@@ -209,7 +209,7 @@ namespace OpenRA.Platforms.Default
 							var lines = p.StandardOutput.ReadToEnd().Split('\n');
 
 							foreach (var line in lines)
-								if (line.StartsWith("Xft.dpi") && int.TryParse(line.Substring(8), out var dpi))
+								if (line.StartsWith("Xft.dpi") && int.TryParse(line[8..], out var dpi))
 									windowScale = dpi / 96f;
 						}
 						catch { }