diff --git a/source/dub/compilers/buildsettings.d b/source/dub/compilers/buildsettings.d
index e752e80..0708615 100644
--- a/source/dub/compilers/buildsettings.d
+++ b/source/dub/compilers/buildsettings.d
@@ -12,6 +12,8 @@
 import std.array : array;
 import std.algorithm : filter;
 import std.path : globMatch;
+static if (__VERSION__ >= 2067)
+	import std.typecons : BitFlags;
 
 
 /// BuildPlatform specific settings, like needed libraries or additional
@@ -94,9 +96,12 @@
 	void addPostGenerateCommands(in string[] value...) { add(postGenerateCommands, value, false); }
 	void addPreBuildCommands(in string[] value...) { add(preBuildCommands, value, false); }
 	void addPostBuildCommands(in string[] value...) { add(postBuildCommands, value, false); }
-	void addRequirements(in BuildRequirements[] value...) { foreach (v; value) this.requirements |= v; }
-	void addOptions(in BuildOptions[] value...) { foreach (v; value) this.options |= v; }
-	void removeOptions(in BuildOptions[] value...) { foreach (v; value) this.options &= ~v; }
+	void addRequirements(in BuildRequirement[] value...) { foreach (v; value) this.requirements |= v; }
+	void addRequirements(in BuildRequirements value) { this.requirements |= value; }
+	void addOptions(in BuildOption[] value...) { foreach (v; value) this.options |= v; }
+	void addOptions(in BuildOptions value) { this.options |= value; }
+	void removeOptions(in BuildOption[] value...) { foreach (v; value) this.options &= ~v; }
+	void removeOptions(in BuildOptions value) { this.options &= ~value; }
 
 	// Adds vals to arr without adding duplicates.
 	private void add(ref string[] arr, in string[] vals, bool no_duplicates = true)
@@ -203,7 +208,7 @@
 	object
 }
 
-enum BuildRequirements {
+enum BuildRequirement {
 	none = 0,                     /// No special requirements
 	allowWarnings        = 1<<0,  /// Warnings do not abort compilation
 	silenceWarnings      = 1<<1,  /// Don't show warnings
@@ -217,7 +222,46 @@
 	noDefaultFlags       = 1<<9,  /// Do not issue any of the default build flags (e.g. -debug, -w, -property etc.) - use only for development purposes
 }
 
-enum BuildOptions {
+	struct BuildRequirements {
+		import dub.internal.vibecompat.data.serialization : ignore;
+
+		static if (__VERSION__ >= 2067) {
+			@ignore BitFlags!BuildRequirement values;
+			this(BuildRequirement req) { values = req; }
+			deprecated("Use BuildRequirement.* instead.") {
+				enum none = BuildRequirement.none;
+				enum allowWarnings = BuildRequirement.allowWarnings;
+				enum silenceWarnings = BuildRequirement.silenceWarnings;
+				enum disallowDeprecations = BuildRequirement.disallowDeprecations;
+				enum silenceDeprecations = BuildRequirement.silenceDeprecations;
+				enum disallowInlining = BuildRequirement.disallowInlining;
+				enum disallowOptimization = BuildRequirement.disallowOptimization;
+				enum requireBoundsCheck = BuildRequirement.requireBoundsCheck;
+				enum requireContracts = BuildRequirement.requireContracts;
+				enum relaxProperties = BuildRequirement.relaxProperties;
+				enum noDefaultFlags = BuildRequirement.noDefaultFlags;
+			}
+		} else {
+			@ignore BuildRequirement values;
+			this(BuildRequirement req) { values = req; }
+			BuildRequirement[] toRepresentation()
+			const {
+				BuildRequirement[] ret;
+				for (int f = 1; f <= BuildRequirement.max; f *= 2)
+					if (values & f) ret ~= cast(BuildRequirement)f;
+				return ret;
+			}
+			static BuildRequirements fromRepresentation(BuildRequirement[] v)
+			{
+				BuildRequirements ret;
+				foreach (f; v) ret.values |= f;
+				return ret;
+			}
+		}
+		alias values this;
+	}
+
+enum BuildOption {
 	none = 0,                     /// Use compiler defaults
 	debugMode = 1<<0,             /// Compile in debug mode (enables contracts, -debug)
 	releaseMode = 1<<1,           /// Compile in release mode (disables assertions and bounds checks, -release)
@@ -241,3 +285,54 @@
 	deprecationErrors = 1<<19,    /// Stop compilation upon usage of deprecated features (-de)
 	property = 1<<20,             /// DEPRECATED: Enforce property syntax (-property)
 }
+
+	struct BuildOptions {
+		import dub.internal.vibecompat.data.serialization : ignore;
+
+		static if (__VERSION__ >= 2067) {
+			@ignore BitFlags!BuildOption values;
+			this(BuildOption opt) { values = opt; }
+			deprecated("Use BuildOption.* instead.") {
+				enum none = BuildOption.none;
+				enum debugMode = BuildOption.debugMode;
+				enum releaseMode = BuildOption.releaseMode;
+				enum coverage = BuildOption.coverage;
+				enum debugInfo = BuildOption.debugInfo;
+				enum debugInfoC = BuildOption.debugInfoC;
+				enum alwaysStackFrame = BuildOption.alwaysStackFrame;
+				enum stackStomping = BuildOption.stackStomping;
+				enum inline = BuildOption.inline;
+				enum noBoundsCheck = BuildOption.noBoundsCheck;
+				enum optimize = BuildOption.optimize;
+				enum profile = BuildOption.profile;
+				enum unittests = BuildOption.unittests;
+				enum verbose = BuildOption.verbose;
+				enum ignoreUnknownPragmas = BuildOption.ignoreUnknownPragmas;
+				enum syntaxOnly = BuildOption.syntaxOnly;
+				enum warnings = BuildOption.warnings;
+				enum warningsAsErrors = BuildOption.warningsAsErrors;
+				enum ignoreDeprecations = BuildOption.ignoreDeprecations;
+				enum deprecationWarnings = BuildOption.deprecationWarnings;
+				enum deprecationErrors = BuildOption.deprecationErrors;
+				enum property = BuildOption.property;
+			}
+		} else {
+			@ignore BuildOption values;
+			this(BuildOption opt) { values = opt; }
+			BuildOption[] toRepresentation()
+			const {
+				BuildOption[] ret;
+				for (int f = 1; f <= BuildOption.max; f *= 2)
+					if (values & f) ret ~= cast(BuildOption)f;
+				return ret;
+			}
+			static BuildOptions fromRepresentation(BuildOption[] v)
+			{
+				BuildOptions ret;
+				foreach (f; v) ret.values |= f;
+				return ret;
+			}
+		}
+
+		alias values this;
+	}
diff --git a/source/dub/compilers/compiler.d b/source/dub/compilers/compiler.d
index 1f47a3d..32ffae3 100644
--- a/source/dub/compilers/compiler.d
+++ b/source/dub/compilers/compiler.d
@@ -106,22 +106,22 @@
 	];
 
 	struct SpecialOption {
-		BuildOptions[] flags;
+		BuildOption[] flags;
 		string alternative;
 	}
 	static immutable SpecialOption[] s_specialOptions = [
-		{[BuildOptions.debugMode], "Call DUB with --build=debug"},
-		{[BuildOptions.releaseMode], "Call DUB with --build=release"},
-		{[BuildOptions.coverage], "Call DUB with --build=cov or --build=unittest-cov"},
-		{[BuildOptions.debugInfo], "Call DUB with --build=debug"},
-		{[BuildOptions.inline], "Call DUB with --build=release"},
-		{[BuildOptions.noBoundsCheck], "Call DUB with --build=release-nobounds"},
-		{[BuildOptions.optimize], "Call DUB with --build=release"},
-		{[BuildOptions.profile], "Call DUB with --build=profile"},
-		{[BuildOptions.unittests], "Call DUB with --build=unittest"},
-		{[BuildOptions.warnings, BuildOptions.warningsAsErrors], "Use \"buildRequirements\" to control the warning level"},
-		{[BuildOptions.ignoreDeprecations, BuildOptions.deprecationWarnings, BuildOptions.deprecationErrors], "Use \"buildRequirements\" to control the deprecation warning level"},
-		{[BuildOptions.property], "This flag is deprecated and has no effect"}
+		{[BuildOption.debugMode], "Call DUB with --build=debug"},
+		{[BuildOption.releaseMode], "Call DUB with --build=release"},
+		{[BuildOption.coverage], "Call DUB with --build=cov or --build=unittest-cov"},
+		{[BuildOption.debugInfo], "Call DUB with --build=debug"},
+		{[BuildOption.inline], "Call DUB with --build=release"},
+		{[BuildOption.noBoundsCheck], "Call DUB with --build=release-nobounds"},
+		{[BuildOption.optimize], "Call DUB with --build=release"},
+		{[BuildOption.profile], "Call DUB with --build=profile"},
+		{[BuildOption.unittests], "Call DUB with --build=unittest"},
+		{[BuildOption.warnings, BuildOption.warningsAsErrors], "Use \"buildRequirements\" to control the warning level"},
+		{[BuildOption.ignoreDeprecations, BuildOption.deprecationWarnings, BuildOption.deprecationErrors], "Use \"buildRequirements\" to control the deprecation warning level"},
+		{[BuildOption.property], "This flag is deprecated and has no effect"}
 	];
 
 	bool got_preamble = false;
@@ -169,16 +169,16 @@
 */
 void enforceBuildRequirements(ref BuildSettings settings)
 {
-	settings.addOptions(BuildOptions.warningsAsErrors);
-	if (settings.requirements & BuildRequirements.allowWarnings) { settings.options &= ~BuildOptions.warningsAsErrors; settings.options |= BuildOptions.warnings; }
-	if (settings.requirements & BuildRequirements.silenceWarnings) settings.options &= ~(BuildOptions.warningsAsErrors|BuildOptions.warnings);
-	if (settings.requirements & BuildRequirements.disallowDeprecations) { settings.options &= ~(BuildOptions.ignoreDeprecations|BuildOptions.deprecationWarnings); settings.options |= BuildOptions.deprecationErrors; }
-	if (settings.requirements & BuildRequirements.silenceDeprecations) { settings.options &= ~(BuildOptions.deprecationErrors|BuildOptions.deprecationWarnings); settings.options |= BuildOptions.ignoreDeprecations; }
-	if (settings.requirements & BuildRequirements.disallowInlining) settings.options &= ~BuildOptions.inline;
-	if (settings.requirements & BuildRequirements.disallowOptimization) settings.options &= ~BuildOptions.optimize;
-	if (settings.requirements & BuildRequirements.requireBoundsCheck) settings.options &= ~BuildOptions.noBoundsCheck;
-	if (settings.requirements & BuildRequirements.requireContracts) settings.options &= ~BuildOptions.releaseMode;
-	if (settings.requirements & BuildRequirements.relaxProperties) settings.options &= ~BuildOptions.property;
+	settings.addOptions(BuildOption.warningsAsErrors);
+	if (settings.requirements & BuildRequirement.allowWarnings) { settings.options &= ~BuildOption.warningsAsErrors; settings.options |= BuildOption.warnings; }
+	if (settings.requirements & BuildRequirement.silenceWarnings) settings.options &= ~(BuildOption.warningsAsErrors|BuildOption.warnings);
+	if (settings.requirements & BuildRequirement.disallowDeprecations) { settings.options &= ~(BuildOption.ignoreDeprecations|BuildOption.deprecationWarnings); settings.options |= BuildOption.deprecationErrors; }
+	if (settings.requirements & BuildRequirement.silenceDeprecations) { settings.options &= ~(BuildOption.deprecationErrors|BuildOption.deprecationWarnings); settings.options |= BuildOption.ignoreDeprecations; }
+	if (settings.requirements & BuildRequirement.disallowInlining) settings.options &= ~BuildOption.inline;
+	if (settings.requirements & BuildRequirement.disallowOptimization) settings.options &= ~BuildOption.optimize;
+	if (settings.requirements & BuildRequirement.requireBoundsCheck) settings.options &= ~BuildOption.noBoundsCheck;
+	if (settings.requirements & BuildRequirement.requireContracts) settings.options &= ~BuildOption.releaseMode;
+	if (settings.requirements & BuildRequirement.relaxProperties) settings.options &= ~BuildOption.property;
 }
 
 
diff --git a/source/dub/compilers/dmd.d b/source/dub/compilers/dmd.d
index 1286c7f..e2fb472 100644
--- a/source/dub/compilers/dmd.d
+++ b/source/dub/compilers/dmd.d
@@ -25,27 +25,27 @@
 
 class DmdCompiler : Compiler {
 	private static immutable s_options = [
-		tuple(BuildOptions.debugMode, ["-debug"]),
-		tuple(BuildOptions.releaseMode, ["-release"]),
-		tuple(BuildOptions.coverage, ["-cov"]),
-		tuple(BuildOptions.debugInfo, ["-g"]),
-		tuple(BuildOptions.debugInfoC, ["-gc"]),
-		tuple(BuildOptions.alwaysStackFrame, ["-gs"]),
-		tuple(BuildOptions.stackStomping, ["-gx"]),
-		tuple(BuildOptions.inline, ["-inline"]),
-		tuple(BuildOptions.noBoundsCheck, ["-noboundscheck"]),
-		tuple(BuildOptions.optimize, ["-O"]),
-		tuple(BuildOptions.profile, ["-profile"]),
-		tuple(BuildOptions.unittests, ["-unittest"]),
-		tuple(BuildOptions.verbose, ["-v"]),
-		tuple(BuildOptions.ignoreUnknownPragmas, ["-ignore"]),
-		tuple(BuildOptions.syntaxOnly, ["-o-"]),
-		tuple(BuildOptions.warnings, ["-wi"]),
-		tuple(BuildOptions.warningsAsErrors, ["-w"]),
-		tuple(BuildOptions.ignoreDeprecations, ["-d"]),
-		tuple(BuildOptions.deprecationWarnings, ["-dw"]),
-		tuple(BuildOptions.deprecationErrors, ["-de"]),
-		tuple(BuildOptions.property, ["-property"]),
+		tuple(BuildOption.debugMode, ["-debug"]),
+		tuple(BuildOption.releaseMode, ["-release"]),
+		tuple(BuildOption.coverage, ["-cov"]),
+		tuple(BuildOption.debugInfo, ["-g"]),
+		tuple(BuildOption.debugInfoC, ["-gc"]),
+		tuple(BuildOption.alwaysStackFrame, ["-gs"]),
+		tuple(BuildOption.stackStomping, ["-gx"]),
+		tuple(BuildOption.inline, ["-inline"]),
+		tuple(BuildOption.noBoundsCheck, ["-noboundscheck"]),
+		tuple(BuildOption.optimize, ["-O"]),
+		tuple(BuildOption.profile, ["-profile"]),
+		tuple(BuildOption.unittests, ["-unittest"]),
+		tuple(BuildOption.verbose, ["-v"]),
+		tuple(BuildOption.ignoreUnknownPragmas, ["-ignore"]),
+		tuple(BuildOption.syntaxOnly, ["-o-"]),
+		tuple(BuildOption.warnings, ["-wi"]),
+		tuple(BuildOption.warningsAsErrors, ["-w"]),
+		tuple(BuildOption.ignoreDeprecations, ["-d"]),
+		tuple(BuildOption.deprecationWarnings, ["-dw"]),
+		tuple(BuildOption.deprecationErrors, ["-de"]),
+		tuple(BuildOption.property, ["-property"]),
 	];
 
 	@property string name() const { return "dmd"; }
diff --git a/source/dub/compilers/gdc.d b/source/dub/compilers/gdc.d
index a82339c..04dbbc7 100644
--- a/source/dub/compilers/gdc.d
+++ b/source/dub/compilers/gdc.d
@@ -25,27 +25,27 @@
 
 class GdcCompiler : Compiler {
 	private static immutable s_options = [
-		tuple(BuildOptions.debugMode, ["-fdebug"]),
-		tuple(BuildOptions.releaseMode, ["-frelease"]),
-		tuple(BuildOptions.coverage, ["-fprofile-arcs", "-ftest-coverage"]),
-		tuple(BuildOptions.debugInfo, ["-g"]),
-		tuple(BuildOptions.debugInfoC, ["-g", "-fdebug-c"]),
-		//tuple(BuildOptions.alwaysStackFrame, ["-X"]),
-		//tuple(BuildOptions.stackStomping, ["-X"]),
-		tuple(BuildOptions.inline, ["-finline-functions"]),
-		tuple(BuildOptions.noBoundsCheck, ["-fno-bounds-check"]),
-		tuple(BuildOptions.optimize, ["-O3"]),
-		tuple(BuildOptions.profile, ["-pg"]),
-		tuple(BuildOptions.unittests, ["-funittest"]),
-		tuple(BuildOptions.verbose, ["-fd-verbose"]),
-		tuple(BuildOptions.ignoreUnknownPragmas, ["-fignore-unknown-pragmas"]),
-		tuple(BuildOptions.syntaxOnly, ["-fsyntax-only"]),
-		tuple(BuildOptions.warnings, ["-Wall"]),
-		tuple(BuildOptions.warningsAsErrors, ["-Werror", "-Wall"]),
-		tuple(BuildOptions.ignoreDeprecations, ["-Wno-deprecated"]),
-		tuple(BuildOptions.deprecationWarnings, ["-Wdeprecated"]),
-		tuple(BuildOptions.deprecationErrors, ["-Werror", "-Wdeprecated"]),
-		tuple(BuildOptions.property, ["-fproperty"]),
+		tuple(BuildOption.debugMode, ["-fdebug"]),
+		tuple(BuildOption.releaseMode, ["-frelease"]),
+		tuple(BuildOption.coverage, ["-fprofile-arcs", "-ftest-coverage"]),
+		tuple(BuildOption.debugInfo, ["-g"]),
+		tuple(BuildOption.debugInfoC, ["-g", "-fdebug-c"]),
+		//tuple(BuildOption.alwaysStackFrame, ["-X"]),
+		//tuple(BuildOption.stackStomping, ["-X"]),
+		tuple(BuildOption.inline, ["-finline-functions"]),
+		tuple(BuildOption.noBoundsCheck, ["-fno-bounds-check"]),
+		tuple(BuildOption.optimize, ["-O3"]),
+		tuple(BuildOption.profile, ["-pg"]),
+		tuple(BuildOption.unittests, ["-funittest"]),
+		tuple(BuildOption.verbose, ["-fd-verbose"]),
+		tuple(BuildOption.ignoreUnknownPragmas, ["-fignore-unknown-pragmas"]),
+		tuple(BuildOption.syntaxOnly, ["-fsyntax-only"]),
+		tuple(BuildOption.warnings, ["-Wall"]),
+		tuple(BuildOption.warningsAsErrors, ["-Werror", "-Wall"]),
+		tuple(BuildOption.ignoreDeprecations, ["-Wno-deprecated"]),
+		tuple(BuildOption.deprecationWarnings, ["-Wdeprecated"]),
+		tuple(BuildOption.deprecationErrors, ["-Werror", "-Wdeprecated"]),
+		tuple(BuildOption.property, ["-fproperty"]),
 	];
 
 	@property string name() const { return "gdc"; }
diff --git a/source/dub/compilers/ldc.d b/source/dub/compilers/ldc.d
index 3dcfa54..35ae0f0 100644
--- a/source/dub/compilers/ldc.d
+++ b/source/dub/compilers/ldc.d
@@ -25,27 +25,27 @@
 
 class LdcCompiler : Compiler {
 	private static immutable s_options = [
-		tuple(BuildOptions.debugMode, ["-d-debug"]),
-		tuple(BuildOptions.releaseMode, ["-release"]),
-		//tuple(BuildOptions.coverage, ["-?"]),
-		tuple(BuildOptions.debugInfo, ["-g"]),
-		tuple(BuildOptions.debugInfoC, ["-gc"]),
-		//tuple(BuildOptions.alwaysStackFrame, ["-?"]),
-		//tuple(BuildOptions.stackStomping, ["-?"]),
-		tuple(BuildOptions.inline, ["-enable-inlining"]),
-		tuple(BuildOptions.noBoundsCheck, ["-disable-boundscheck"]),
-		tuple(BuildOptions.optimize, ["-O"]),
-		//tuple(BuildOptions.profile, ["-?"]),
-		tuple(BuildOptions.unittests, ["-unittest"]),
-		tuple(BuildOptions.verbose, ["-v"]),
-		tuple(BuildOptions.ignoreUnknownPragmas, ["-ignore"]),
-		tuple(BuildOptions.syntaxOnly, ["-o-"]),
-		tuple(BuildOptions.warnings, ["-wi"]),
-		tuple(BuildOptions.warningsAsErrors, ["-w"]),
-		tuple(BuildOptions.ignoreDeprecations, ["-d"]),
-		tuple(BuildOptions.deprecationWarnings, ["-dw"]),
-		tuple(BuildOptions.deprecationErrors, ["-de"]),
-		tuple(BuildOptions.property, ["-property"]),
+		tuple(BuildOption.debugMode, ["-d-debug"]),
+		tuple(BuildOption.releaseMode, ["-release"]),
+		//tuple(BuildOption.coverage, ["-?"]),
+		tuple(BuildOption.debugInfo, ["-g"]),
+		tuple(BuildOption.debugInfoC, ["-gc"]),
+		//tuple(BuildOption.alwaysStackFrame, ["-?"]),
+		//tuple(BuildOption.stackStomping, ["-?"]),
+		tuple(BuildOption.inline, ["-enable-inlining"]),
+		tuple(BuildOption.noBoundsCheck, ["-disable-boundscheck"]),
+		tuple(BuildOption.optimize, ["-O"]),
+		//tuple(BuildOption.profile, ["-?"]),
+		tuple(BuildOption.unittests, ["-unittest"]),
+		tuple(BuildOption.verbose, ["-v"]),
+		tuple(BuildOption.ignoreUnknownPragmas, ["-ignore"]),
+		tuple(BuildOption.syntaxOnly, ["-o-"]),
+		tuple(BuildOption.warnings, ["-wi"]),
+		tuple(BuildOption.warningsAsErrors, ["-w"]),
+		tuple(BuildOption.ignoreDeprecations, ["-d"]),
+		tuple(BuildOption.deprecationWarnings, ["-dw"]),
+		tuple(BuildOption.deprecationErrors, ["-de"]),
+		tuple(BuildOption.property, ["-property"]),
 	];
 
 	@property string name() const { return "ldc"; }
diff --git a/source/dub/description.d b/source/dub/description.d
index 7c7e22c..64eda56 100644
--- a/source/dub/description.d
+++ b/source/dub/description.d
@@ -61,8 +61,8 @@
 	string[] postGenerateCommands;
 	string[] preBuildCommands;
 	string[] postBuildCommands;
-	@byName BuildRequirements[] buildRequirements;
-	@byName BuildOptions[] options;
+	@byName BuildRequirement[] buildRequirements;
+	@byName BuildOption[] options;
 	SourceFileDescription[] files;
 }
 
diff --git a/source/dub/generators/build.d b/source/dub/generators/build.d
index ee949fe..e453047 100644
--- a/source/dub/generators/build.d
+++ b/source/dub/generators/build.d
@@ -82,7 +82,7 @@
 	{
 		// run the generated executable
 		auto buildsettings = targets[m_project.rootPackage.name].buildSettings;
-		if (settings.run && !(buildsettings.options & BuildOptions.syntaxOnly)) {
+		if (settings.run && !(buildsettings.options & BuildOption.syntaxOnly)) {
 			auto exe_file_path = Path(buildsettings.targetPath) ~ getTargetFileName(buildsettings, settings.platform);
 			runTarget(exe_file_path, buildsettings, settings.runArgs, settings);
 		}
@@ -91,7 +91,7 @@
 	private void buildTarget(GeneratorSettings settings, BuildSettings buildsettings, in Package pack, string config, in Package[] packages, in Path[] additional_dep_files)
 	{
 		auto cwd = Path(getcwd());
-		bool generate_binary = !(buildsettings.options & BuildOptions.syntaxOnly);
+		bool generate_binary = !(buildsettings.options & BuildOption.syntaxOnly);
 
 		auto build_id = computeBuildID(config, buildsettings, settings);
 
@@ -134,7 +134,7 @@
 		}
 
 		// determine basic build properties
-		auto generate_binary = !(buildsettings.options & BuildOptions.syntaxOnly);
+		auto generate_binary = !(buildsettings.options & BuildOption.syntaxOnly);
 
 		logInfo("Building %s %s configuration \"%s\", build type %s.", pack.name, pack.vers, config, settings.buildType);
 
@@ -223,7 +223,7 @@
 	{
 		auto cwd = Path(getcwd());
 
-		auto generate_binary = !(buildsettings.options & BuildOptions.syntaxOnly);
+		auto generate_binary = !(buildsettings.options & BuildOption.syntaxOnly);
 		auto is_static_library = buildsettings.targetType == TargetType.staticLibrary || buildsettings.targetType == TargetType.library;
 
 		// make file paths relative to shrink the command line
@@ -373,7 +373,7 @@
 
 	void buildWithCompiler(GeneratorSettings settings, BuildSettings buildsettings)
 	{
-		auto generate_binary = !(buildsettings.options & BuildOptions.syntaxOnly);
+		auto generate_binary = !(buildsettings.options & BuildOption.syntaxOnly);
 		auto is_static_library = buildsettings.targetType == TargetType.staticLibrary || buildsettings.targetType == TargetType.library;
 
 		Path target_file;
diff --git a/source/dub/generators/generator.d b/source/dub/generators/generator.d
index 5b8db64..ab16f72 100644
--- a/source/dub/generators/generator.d
+++ b/source/dub/generators/generator.d
@@ -108,7 +108,7 @@
 		foreach (pack; m_project.getTopologicalPackageList(true, null, configs)) {
 			BuildSettings buildsettings;
 			buildsettings.processVars(m_project, pack, pack.getBuildSettings(settings.platform, configs[pack.name]), true);
-			bool generate_binary = !(buildsettings.options & BuildOptions.syntaxOnly);
+			bool generate_binary = !(buildsettings.options & BuildOption.syntaxOnly);
 			finalizeGeneration(pack.name, buildsettings, pack.path, Path(bs.targetPath), generate_binary);
 		}
 
@@ -219,7 +219,7 @@
 			m_project.addBuildTypeSettings(buildsettings, settings.platform, settings.buildType);
 			settings.compiler.extractBuildOptions(buildsettings);
 
-			enforce (generates_binary || pack !is m_project.rootPackage || (buildsettings.options & BuildOptions.syntaxOnly),
+			enforce (generates_binary || pack !is m_project.rootPackage || (buildsettings.options & BuildOption.syntaxOnly),
 				format("Main package must have a binary target type, not %s. Cannot build.", tt));
 
 			targets[pack.name].buildSettings = buildsettings.dup;
diff --git a/source/dub/generators/visuald.d b/source/dub/generators/visuald.d
index 49f35aa..ca64372 100644
--- a/source/dub/generators/visuald.d
+++ b/source/dub/generators/visuald.d
@@ -257,10 +257,10 @@
 				ret.formattedWrite("  <Config name=\"%s\" platform=\"%s\">\n", to!string(type), arch);
 
 				// debug and optimize setting
-				ret.formattedWrite("    <symdebug>%s</symdebug>\n", buildsettings.options & BuildOptions.debugInfo ? "1" : "0");
-				ret.formattedWrite("    <optimize>%s</optimize>\n", buildsettings.options & BuildOptions.optimize ? "1" : "0");
-				ret.formattedWrite("    <useInline>%s</useInline>\n", buildsettings.options & BuildOptions.inline ? "1" : "0");
-				ret.formattedWrite("    <release>%s</release>\n", buildsettings.options & BuildOptions.releaseMode ? "1" : "0");
+				ret.formattedWrite("    <symdebug>%s</symdebug>\n", buildsettings.options & BuildOption.debugInfo ? "1" : "0");
+				ret.formattedWrite("    <optimize>%s</optimize>\n", buildsettings.options & BuildOption.optimize ? "1" : "0");
+				ret.formattedWrite("    <useInline>%s</useInline>\n", buildsettings.options & BuildOption.inline ? "1" : "0");
+				ret.formattedWrite("    <release>%s</release>\n", buildsettings.options & BuildOption.releaseMode ? "1" : "0");
 
 				// Lib or exe?
 				enum
@@ -308,7 +308,7 @@
 				if (output_type != StaticLib) ret.formattedWrite("    <libfiles>%s %s</libfiles>\n", linkLibs, addLinkFiles);
 
 				// Unittests
-				ret.formattedWrite("    <useUnitTests>%s</useUnitTests>\n", buildsettings.options & BuildOptions.unittests ? "1" : "0");
+				ret.formattedWrite("    <useUnitTests>%s</useUnitTests>\n", buildsettings.options & BuildOption.unittests ? "1" : "0");
 
 				// compute directory for intermediate files (need dummy/ because of how -op determines the resulting path)
 				size_t ndummy = 0;
@@ -337,7 +337,7 @@
 				ret.put("    <oneobj>0</oneobj>\n");
 				ret.put("    <trace>0</trace>\n");
 				ret.put("    <quiet>0</quiet>\n");
-				ret.formattedWrite("    <verbose>%s</verbose>\n", buildsettings.options & BuildOptions.verbose ? "1" : "0");
+				ret.formattedWrite("    <verbose>%s</verbose>\n", buildsettings.options & BuildOption.verbose ? "1" : "0");
 				ret.put("    <vtls>0</vtls>\n");
 				ret.put("    <cpu>0</cpu>\n");
 				ret.formattedWrite("    <isX86_64>%s</isX86_64>\n", arch == "x64" ? 1 : 0);
@@ -353,18 +353,18 @@
 				ret.put("    <useIn>0</useIn>\n");
 				ret.put("    <useOut>0</useOut>\n");
 				ret.put("    <useArrayBounds>0</useArrayBounds>\n");
-				ret.formattedWrite("    <noboundscheck>%s</noboundscheck>\n", buildsettings.options & BuildOptions.noBoundsCheck ? "1" : "0");
+				ret.formattedWrite("    <noboundscheck>%s</noboundscheck>\n", buildsettings.options & BuildOption.noBoundsCheck ? "1" : "0");
 				ret.put("    <useSwitchError>0</useSwitchError>\n");
 				ret.put("    <preservePaths>1</preservePaths>\n");
-				ret.formattedWrite("    <warnings>%s</warnings>\n", buildsettings.options & BuildOptions.warningsAsErrors ? "1" : "0");
-				ret.formattedWrite("    <infowarnings>%s</infowarnings>\n", buildsettings.options & BuildOptions.warnings ? "1" : "0");
-				ret.formattedWrite("    <checkProperty>%s</checkProperty>\n", buildsettings.options & BuildOptions.property ? "1" : "0");
-				ret.formattedWrite("    <genStackFrame>%s</genStackFrame>\n", buildsettings.options & BuildOptions.alwaysStackFrame ? "1" : "0");
+				ret.formattedWrite("    <warnings>%s</warnings>\n", buildsettings.options & BuildOption.warningsAsErrors ? "1" : "0");
+				ret.formattedWrite("    <infowarnings>%s</infowarnings>\n", buildsettings.options & BuildOption.warnings ? "1" : "0");
+				ret.formattedWrite("    <checkProperty>%s</checkProperty>\n", buildsettings.options & BuildOption.property ? "1" : "0");
+				ret.formattedWrite("    <genStackFrame>%s</genStackFrame>\n", buildsettings.options & BuildOption.alwaysStackFrame ? "1" : "0");
 				ret.put("    <pic>0</pic>\n");
-				ret.formattedWrite("    <cov>%s</cov>\n", buildsettings.options & BuildOptions.coverage ? "1" : "0");
+				ret.formattedWrite("    <cov>%s</cov>\n", buildsettings.options & BuildOption.coverage ? "1" : "0");
 				ret.put("    <nofloat>0</nofloat>\n");
 				ret.put("    <Dversion>2</Dversion>\n");
-				ret.formattedWrite("    <ignoreUnsupportedPragmas>%s</ignoreUnsupportedPragmas>\n", buildsettings.options & BuildOptions.ignoreUnknownPragmas ? "1" : "0");
+				ret.formattedWrite("    <ignoreUnsupportedPragmas>%s</ignoreUnsupportedPragmas>\n", buildsettings.options & BuildOption.ignoreUnknownPragmas ? "1" : "0");
 				ret.formattedWrite("    <compiler>%s</compiler>\n", settings.compiler.name == "ldc" ? 2 : settings.compiler.name == "gdc" ? 1 : 0);
 				ret.formattedWrite("    <otherDMD>0</otherDMD>\n");
 				ret.formattedWrite("    <outdir>%s</outdir>\n", bin_path.toNativeString());
diff --git a/source/dub/internal/vibecompat/data/serialization.d b/source/dub/internal/vibecompat/data/serialization.d
index c68cde0..6903a05 100644
--- a/source/dub/internal/vibecompat/data/serialization.d
+++ b/source/dub/internal/vibecompat/data/serialization.d
@@ -450,7 +450,7 @@
 private T deserializeImpl(T, alias Policy, Serializer, ATTRIBUTES...)(ref Serializer deserializer)
 {
 	import std.typecons : Nullable;
-	static if (__VERSION__ >= 2067) import std.typecons : ButFlags;
+	static if (__VERSION__ >= 2067) import std.typecons : BitFlags;
 
 	static assert(Serializer.isSupportedValueType!string, "All serializers must support string values.");
 	static assert(Serializer.isSupportedValueType!(typeof(null)), "All serializers must support null values.");
diff --git a/source/dub/internal/vibecompat/data/utils.d b/source/dub/internal/vibecompat/data/utils.d
index a171fe3..7d4359c 100644
--- a/source/dub/internal/vibecompat/data/utils.d
+++ b/source/dub/internal/vibecompat/data/utils.d
@@ -240,7 +240,8 @@
 	static if (!__traits(compiles, TypeTuple!(__traits(getMember, T, M)))) enum isPublicMember = false;
 	else {
 		alias MEM = TypeTuple!(__traits(getMember, T, M));
-		enum isPublicMember = __traits(getProtection, MEM).among("public", "export");
+		enum _prot =  __traits(getProtection, MEM);
+		enum isPublicMember = _prot == "public" || _prot == "export";
 	}
 }
 
diff --git a/source/dub/package_.d b/source/dub/package_.d
index c6eaa05..5af1912 100644
--- a/source/dub/package_.d
+++ b/source/dub/package_.d
@@ -287,7 +287,7 @@
 			logDiagnostic("Using custom build type '%s'.", build_type);
 			pbt.getPlatformSettings(settings, platform, this.path);
 		} else {
-			with(BuildOptions) switch (build_type) {
+			with(BuildOption) switch (build_type) {
 				default: throw new Exception(format("Unknown build type for %s: '%s'", this.name, build_type));
 				case "plain": break;
 				case "debug": settings.addOptions(debugMode, debugInfo); break;
@@ -401,14 +401,14 @@
 		ret.postBuildCommands = bs.postBuildCommands;
 
 		// prettify build requirements output
-		for (int i = 1; i <= BuildRequirements.max; i <<= 1)
-			if (bs.requirements & i)
-				ret.buildRequirements ~= cast(BuildRequirements)i;
+		for (int i = 1; i <= BuildRequirement.max; i <<= 1)
+			if (bs.requirements & cast(BuildRequirement)i)
+				ret.buildRequirements ~= cast(BuildRequirement)i;
 
 		// prettify options output
-		for (int i = 1; i <= BuildOptions.max; i <<= 1)
-			if (bs.options & i)
-				ret.options ~= cast(BuildOptions)i;
+		for (int i = 1; i <= BuildOption.max; i <<= 1)
+			if (bs.options & cast(BuildOption)i)
+				ret.options ~= cast(BuildOption)i;
 
 		// collect all possible source files and determine their types
 		SourceFileRole[string] sourceFileTypes;
diff --git a/source/dub/project.d b/source/dub/project.d
index c4b104c..36a1ab6 100644
--- a/source/dub/project.d
+++ b/source/dub/project.d
@@ -531,7 +531,7 @@
 
 	void addBuildTypeSettings(ref BuildSettings dst, in BuildPlatform platform, string build_type)
 	{
-		bool usedefflags = !(dst.requirements & BuildRequirements.noDefaultFlags);
+		bool usedefflags = !(dst.requirements & BuildRequirement.noDefaultFlags);
 		if (usedefflags) {
 			BuildSettings btsettings;
 			m_rootPackage.addBuildTypeSettings(btsettings, platform, build_type);
diff --git a/source/dub/recipe/json.d b/source/dub/recipe/json.d
index 2ffe0a9..24cb3f7 100644
--- a/source/dub/recipe/json.d
+++ b/source/dub/recipe/json.d
@@ -221,13 +221,13 @@
 			case "buildRequirements":
 				BuildRequirements reqs;
 				foreach (req; deserializeJson!(string[])(value))
-					reqs |= to!BuildRequirements(req);
+					reqs |= to!BuildRequirement(req);
 				bs.buildRequirements[suffix] = reqs;
 				break;
 			case "buildOptions":
 				BuildOptions options;
 				foreach (opt; deserializeJson!(string[])(value))
-					options |= to!BuildOptions(opt);
+					options |= to!BuildOption(opt);
 				bs.buildOptions[suffix] = options;
 				break;
 		}
@@ -266,13 +266,13 @@
 	foreach (suffix, arr; bs.postBuildCommands) ret["postBuildCommands"~suffix] = serializeToJson(arr);
 	foreach (suffix, arr; bs.buildRequirements) {
 		string[] val;
-		foreach (i; [EnumMembers!BuildRequirements])
+		foreach (i; [EnumMembers!BuildRequirement])
 			if (arr & i) val ~= to!string(i);
 		ret["buildRequirements"~suffix] = serializeToJson(val);
 	}
 	foreach (suffix, arr; bs.buildOptions) {
 		string[] val;
-		foreach (i; [EnumMembers!BuildOptions])
+		foreach (i; [EnumMembers!BuildOption])
 			if (arr & i) val ~= to!string(i);
 		ret["buildOptions"~suffix] = serializeToJson(val);
 	}
diff --git a/source/dub/recipe/packagerecipe.d b/source/dub/recipe/packagerecipe.d
index d844424..0a26059 100644
--- a/source/dub/recipe/packagerecipe.d
+++ b/source/dub/recipe/packagerecipe.d
@@ -235,8 +235,8 @@
 		auto nodef = false;
 		auto noprop = false;
 		foreach (req; this.buildRequirements) {
-			if (req & BuildRequirements.noDefaultFlags) nodef = true;
-			if (req & BuildRequirements.relaxProperties) noprop = true;
+			if (req & BuildRequirement.noDefaultFlags) nodef = true;
+			if (req & BuildRequirement.relaxProperties) noprop = true;
 		}
 
 		if (noprop) {
diff --git a/source/dub/recipe/sdl.d b/source/dub/recipe/sdl.d
index 5b1b173..6a82abb 100644
--- a/source/dub/recipe/sdl.d
+++ b/source/dub/recipe/sdl.d
@@ -112,8 +112,8 @@
 		case "postGenerateCommands": setting.parsePlatformStringArray(bs.postGenerateCommands); break;
 		case "preBuildCommands": setting.parsePlatformStringArray(bs.preBuildCommands); break;
 		case "postBuildCommands": setting.parsePlatformStringArray(bs.postBuildCommands); break;
-		case "buildRequirements": setting.parsePlatformEnumArray!BuildRequirements(bs.buildRequirements); break;
-		case "buildOptions": setting.parsePlatformEnumArray!BuildOptions(bs.buildOptions); break;
+		case "buildRequirements": setting.parsePlatformEnumArray!BuildRequirement(bs.buildRequirements); break;
+		case "buildOptions": setting.parsePlatformEnumArray!BuildOption(bs.buildOptions); break;
 	}
 }
 
@@ -205,8 +205,10 @@
 	string platform;
 	if ("platform" in t.attributes)
 		platform = t.attributes["platform"][0].value.get!string;
-	foreach (v; t.values)
+	foreach (v; t.values) {
+		if (platform !in dst) dst[platform] = Es.init;
 		dst[platform] |= v.get!string.to!E;
+	}
 }
 
 private void enforceSDL(bool condition, lazy string message, Tag tag, string file = __FILE__, int line = __LINE__)
@@ -334,8 +336,8 @@
 	assert(rec.buildSettings.workingDirectory == "working directory");
 	assert(rec.buildSettings.subConfigurations.length == 1);
 	assert(rec.buildSettings.subConfigurations["projectname:subpackage2"] == "library");
-	assert(rec.buildSettings.buildRequirements == ["": BuildRequirements.allowWarnings | BuildRequirements.silenceDeprecations]);
-	assert(rec.buildSettings.buildOptions == ["": BuildOptions.verbose | BuildOptions.ignoreUnknownPragmas]);
+	assert(rec.buildSettings.buildRequirements == ["": cast(BuildRequirements)(BuildRequirement.allowWarnings | BuildRequirement.silenceDeprecations)]);
+	assert(rec.buildSettings.buildOptions == ["": cast(BuildOptions)(BuildOption.verbose | BuildOption.ignoreUnknownPragmas)]);
 	assert(rec.buildSettings.libs == ["": ["lib1", "lib2", "lib3"]]);
 	assert(rec.buildSettings.sourceFiles == ["": ["source1", "source2", "source3"]]);
 	assert(rec.buildSettings.sourcePaths == ["": ["sourcepath1", "sourcepath2", "sourcepath3"]]);