diff --git a/source/dub/commandline.d b/source/dub/commandline.d
index 9eb26aa..1027daa 100644
--- a/source/dub/commandline.d
+++ b/source/dub/commandline.d
@@ -61,6 +61,7 @@
 		bool rdmd = false;
 		bool print_platform, print_builds, print_configs;
 		bool place_system_wide = false, place_locally = false;
+		bool pre_release = false;
 		string retrieved_version;
 		string[] registry_urls;
 		string[] debug_versions;
@@ -84,6 +85,7 @@
 			"print-platform", &print_platform,
 			"system", &place_system_wide,
 			"local", &place_locally,
+			"prerelease", &pre_release,
 			"version", &retrieved_version,
 			"registry", &registry_urls,
 			"root", &root_path
@@ -190,7 +192,7 @@
 			case "upgrade":
 				dub.loadPackageFromCwd();
 				logInfo("Upgrading project in %s", dub.projectPath.toNativeString());
-				dub.update(UpdateOptions.Upgrade | (annotate ? UpdateOptions.JustAnnotate : UpdateOptions.None));
+				dub.update(UpdateOptions.Upgrade | (annotate ? UpdateOptions.JustAnnotate : UpdateOptions.None) | (pre_release ? UpdateOptions.preRelease : UpdateOptions.None));
 				return 0;
 			case "install":
 				warnRenamed(cmd, "fetch");
@@ -202,10 +204,10 @@
 				enforce(!place_locally || !place_system_wide, "Cannot place package locally and system wide at the same time.");
 				if (place_locally) location = PlacementLocation.local;
 				else if (place_system_wide) location = PlacementLocation.systemWide;
-				if (retrieved_version.length) dub.fetch(name, Dependency(retrieved_version), location, true);
+				if (retrieved_version.length) dub.fetch(name, Dependency(retrieved_version), location, true, false);
 				else {
 					try {
-						dub.fetch(name, Dependency(">=0.0.0"), location, true);
+						dub.fetch(name, Dependency(">=0.0.0"), location, true, false);
 						logInfo(
 							"Please note that you need to use `dub run <pkgname>` " ~ 
 							"or add it to dependencies of your package to actually use/run it. " ~
@@ -214,7 +216,7 @@
 					catch(Exception e){
 						logInfo("Getting a release version failed: %s", e.msg);
 						logInfo("Retry with ~master...");
-						dub.fetch(name, Dependency("~master"), location, true);
+						dub.fetch(name, Dependency("~master"), location, true, true);
 					}
 				}
 				break;
@@ -439,8 +441,14 @@
 
 Fetch/remove options:
         --version        Use the specified version/branch instead of the latest
-        --system         Put package into system wide dub cache instead of user local one
-        --local          Put packahe to a sub folder of the current directory
+        --system         Put package into system wide dub cache instead of the
+                         user local one
+        --local          Extract the package to a sub folder of the current
+                         working directory
+
+Upgrade options:
+        -prerelease      Uses the latest pre-release version, even if release
+                         versions are available
 
 `);
 	logInfo("DUB version %s", dubVersion);
diff --git a/source/dub/dependency.d b/source/dub/dependency.d
index 669a2dc..8807988 100644
--- a/source/dub/dependency.d
+++ b/source/dub/dependency.d
@@ -60,6 +60,10 @@
 	/// Returns true, if this version indicates a branch, which is not the trunk.
 	@property bool isBranch() const { return m_version[0] == BRANCH_IDENT && m_version != MASTER_STRING; }
 	@property bool isMaster() const { return m_version == MASTER_STRING; }
+	@property bool isPreRelease() const {
+		if (isBranch || isMaster) return true;
+		return isPreReleaseVersion(m_version);
+	}
 
 	/** 
 		Comparing Versions is generally possible, but comparing Versions 
diff --git a/source/dub/dub.d b/source/dub/dub.d
index d2c814e..bfe1b4c 100644
--- a/source/dub/dub.d
+++ b/source/dub/dub.d
@@ -168,7 +168,7 @@
 				remove(a.pack);
 			}
 			foreach(Action a; filter!((Action a) => a.type == Action.Type.fetch)(actions)) {
-				fetch(a.packageId, a.vers, a.location, (options & UpdateOptions.Upgrade) != 0);
+				fetch(a.packageId, a.vers, a.location, (options & UpdateOptions.Upgrade) != 0, (options & UpdateOptions.preRelease) != 0);
 				// never update the same package more than once
 				masterVersionUpgrades[a.packageId] = true;
 			}
@@ -202,13 +202,13 @@
 	string[string] cachedPackages() const { return m_project.cachedPackagesIDs(); }
 
 	/// Fetches the package matching the dependency and places it in the specified location.
-	Package fetch(string packageId, const Dependency dep, PlacementLocation location, bool force_branch_upgrade)
+	Package fetch(string packageId, const Dependency dep, PlacementLocation location, bool force_branch_upgrade, bool use_prerelease)
 	{
 		Json pinfo;
 		PackageSupplier supplier;
 		foreach(ps; m_packageSuppliers){
 			try {
-				pinfo = ps.getPackageDescription(packageId, dep);
+				pinfo = ps.getPackageDescription(packageId, dep, use_prerelease);
 				supplier = ps;
 				break;
 			} catch(Exception) {}
@@ -244,7 +244,7 @@
 		auto tempFile = m_tempPath ~ tempfname;
 		string sTempFile = tempFile.toNativeString();
 		if (exists(sTempFile)) std.file.remove(sTempFile);
-		supplier.retrievePackage(tempFile, packageId, dep); // Q: continue on fail?
+		supplier.retrievePackage(tempFile, packageId, dep, use_prerelease); // Q: continue on fail?
 		scope(exit) std.file.remove(sTempFile);
 
 		logInfo("Placing %s %s to %s...", packageId, ver, placement.toNativeString());
@@ -370,7 +370,7 @@
 		if (!ddox_pack) ddox_pack = m_packageManager.getBestPackage("ddox", "~master");
 		if (!ddox_pack) {
 			logInfo("DDOX is not present, getting it and storing user wide");
-			ddox_pack = fetch("ddox", Dependency(">=0.0.0"), PlacementLocation.userWide, false);
+			ddox_pack = fetch("ddox", Dependency(">=0.0.0"), PlacementLocation.userWide, false, false);
 		}
 
 		version(Windows) auto ddox_exe = "ddox.exe";
diff --git a/source/dub/packagesupplier.d b/source/dub/packagesupplier.d
index 53e593c..e15a315 100644
--- a/source/dub/packagesupplier.d
+++ b/source/dub/packagesupplier.d
@@ -23,10 +23,10 @@
 /// which is available.
 interface PackageSupplier {
 	/// path: absolute path to store the package (usually in a zip format)
-	void retrievePackage(Path path, string packageId, Dependency dep);
+	void retrievePackage(Path path, string packageId, Dependency dep, bool pre_release);
 	
 	/// returns the metadata for the package
-	Json getPackageDescription(string packageId, Dependency dep);
+	Json getPackageDescription(string packageId, Dependency dep, bool pre_release);
 
 	/// Returns a hunman readable representation of the supplier
 	string toString();
@@ -41,39 +41,43 @@
 
 	override string toString() { return "file repository at "~m_path.toNativeString(); }
 	
-	void retrievePackage(Path path, string packageId, Dependency dep)
+	void retrievePackage(Path path, string packageId, Dependency dep, bool pre_release)
 	{
 		enforce(path.absolute);
 		logInfo("Storing package '"~packageId~"', version requirements: %s", dep);
-		auto filename = bestPackageFile(packageId, dep);
+		auto filename = bestPackageFile(packageId, dep, pre_release);
 		enforce(existsFile(filename));
 		copyFile(filename, path);
 	}
 	
-	Json getPackageDescription(string packageId, Dependency dep)
+	Json getPackageDescription(string packageId, Dependency dep, bool pre_release)
 	{
-		auto filename = bestPackageFile(packageId, dep);
+		auto filename = bestPackageFile(packageId, dep, pre_release);
 		return jsonFromZip(filename, "package.json");
 	}
 	
-	private Path bestPackageFile(string packageId, Dependency dep)
+	private Path bestPackageFile(string packageId, Dependency dep, bool pre_release)
 	const {
-		Version bestVersion = Version.RELEASE;
+		Version bestver = Version.RELEASE;
 		foreach (DirEntry d; dirEntries(m_path.toNativeString(), packageId~"*", SpanMode.shallow)) {
 			Path p = Path(d.name);
 			logDebug("Entry: %s", p);
 			enforce(to!string(p.head)[$-4..$] == ".zip");
 			string vers = to!string(p.head)[packageId.length+1..$-4];
 			logDebug("Version string: "~vers);
-			Version v = Version(vers);
-			if (v > bestVersion && dep.matches(v)) {
-				bestVersion = v;
-			}
+			Version cur = Version(vers);
+			if (!dep.matches(cur)) continue;
+			if (bestver == Version.RELEASE) bestver = cur;
+			else if (pre_release) {
+				if (cur > bestver) bestver = cur;
+			} else if (bestver.isPreRelease) {
+				if (!cur.isPreRelease || cur > bestver) bestver = cur;
+			} else if (!cur.isPreRelease && cur > bestver) bestver = cur;
 		}
 		
-		auto fileName = m_path ~ (packageId ~ "_" ~ to!string(bestVersion) ~ ".zip");
+		auto fileName = m_path ~ (packageId ~ "_" ~ to!string(bestver) ~ ".zip");
 		
-		if (bestVersion == Version.RELEASE || !existsFile(fileName))
+		if (bestver == Version.RELEASE || !existsFile(fileName))
 			throw new Exception("No matching package found");
 		
 		logDiagnostic("Found best matching package: '%s'", fileName);
@@ -96,17 +100,17 @@
 
 	override string toString() { return "registry at "~m_registryUrl.toString(); }
 	
-	void retrievePackage(Path path, string packageId, Dependency dep)
+	void retrievePackage(Path path, string packageId, Dependency dep, bool pre_release)
 	{
-		Json best = getBestPackage(packageId, dep);
+		Json best = getBestPackage(packageId, dep, pre_release);
 		auto url = m_registryUrl ~ Path(PackagesPath~"/"~packageId~"/"~best["version"].get!string~".zip");
 		logDiagnostic("Found download URL: '%s'", url);
 		download(url, path);
 	}
 	
-	Json getPackageDescription(string packageId, Dependency dep)
+	Json getPackageDescription(string packageId, Dependency dep, bool pre_release)
 	{
-		return getBestPackage(packageId, dep);
+		return getBestPackage(packageId, dep, pre_release);
 	}
 	
 	private Json getMetadata(string packageId)
@@ -125,14 +129,22 @@
 		return json;
 	}
 	
-	private Json getBestPackage(string packageId, Dependency dep)
+	private Json getBestPackage(string packageId, Dependency dep, bool pre_release)
 	{
 		Json md = getMetadata(packageId);
 		Json best = null;
+		Version bestver;
 		foreach (json; md["versions"]) {
 			auto cur = Version(cast(string)json["version"]);
-			if (dep.matches(cur) && (best == null || Version(cast(string)best["version"]) < cur))
-				best = json;
+			logInfo("FOUND %s %s %s", cur.toString(), dep.matches(cur), cur.isPreRelease);
+			if (!dep.matches(cur)) continue;
+			if (best == null) best = json;
+			else if (pre_release) {
+				if (cur > bestver) best = json;
+			} else if (bestver.isPreRelease) {
+				if (!cur.isPreRelease || cur > bestver) best = json;
+			} else if (!cur.isPreRelease && cur > bestver) best = json;
+			bestver = Version(cast(string)best["version"]);
 		}
 		enforce(best != null, "No package candidate found for "~packageId~" "~dep.toString());
 		return best;
diff --git a/source/dub/project.d b/source/dub/project.d
index a5b09a2..bcbb705 100644
--- a/source/dub/project.d
+++ b/source/dub/project.d
@@ -584,7 +584,7 @@
 						logDiagnostic("Fetching package %s (%d suppliers registered)", pkg, packageSuppliers.length);
 						foreach (ps; packageSuppliers) {
 							try {
-								auto sp = new Package(ps.getPackageDescription(ppath[0], reqDep.dependency));
+								auto sp = new Package(ps.getPackageDescription(ppath[0], reqDep.dependency, false));
 								foreach (spn; ppath[1 .. $])
 									sp = sp.getSubPackage(spn);
 								p = sp;
@@ -726,7 +726,8 @@
 {
 	None = 0,
 	JustAnnotate = 1<<0,
-	Upgrade = 1<<1
+	Upgrade = 1<<1,
+	preRelease = 1<<2 // inclde pre-release versions in upgrade
 }
 
 
diff --git a/source/dub/semver.d b/source/dub/semver.d
index 8f81411..b6b1607 100644
--- a/source/dub/semver.d
+++ b/source/dub/semver.d
@@ -91,6 +91,18 @@
 	assert(!isValidVersion("1.0-1.0"));
 }
 
+bool isPreReleaseVersion(string ver)
+in { assert(isValidVersion(ver)); }
+body {
+	foreach (i; 0 .. 2) {
+		auto di = ver.indexOf('.');
+		assert(di > 0);
+		ver = ver[di+1 .. $];
+	}
+	auto di = ver.indexOf('-');
+	if (di < 0) return false;
+	return isValidNumber(ver[0 .. di]);
+}
 
 /**
 	Compares the precedence of two SemVer version strings.