diff --git a/build/Avalonia.Desktop.props b/build/Avalonia.Desktop.props
index 8b4b4e7fd..84c56be3b 100644
--- a/build/Avalonia.Desktop.props
+++ b/build/Avalonia.Desktop.props
@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="utf-8"?>
 <Project DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
   <ItemGroup>
-    <PackageReference Include="Avalonia.Desktop" Version="0.9.0-preview3" />
+    <PackageReference Include="Avalonia.Desktop" Version="0.9.0-preview4" />
     <PackageReference Include="Avalonia.Angle.Windows.Natives" Version="2.1.0.2019013001" />
   </ItemGroup>
 </Project>
diff --git a/build/Avalonia.props b/build/Avalonia.props
index 8c6cc2da3..3e6556ec6 100644
--- a/build/Avalonia.props
+++ b/build/Avalonia.props
@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="utf-8"?>
 <Project DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
   <ItemGroup>
-    <PackageReference Include="Avalonia" Version="0.9.0-preview3" />
+    <PackageReference Include="Avalonia" Version="0.9.0-preview4" />
   </ItemGroup>
 </Project>
diff --git a/build/Base.props b/build/Base.props
index 4c0386cf7..09c0752d6 100644
--- a/build/Base.props
+++ b/build/Base.props
@@ -1,8 +1,8 @@
 <?xml version="1.0" encoding="utf-8"?>
 <Project DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
   <PropertyGroup>
-    <VersionPrefix>0.9.1</VersionPrefix>
-    <VersionSuffix></VersionSuffix>
+    <VersionPrefix>0.9.0</VersionPrefix>
+    <VersionSuffix>preview4</VersionSuffix>
     <Authors>Wiesław Šoltés</Authors>
     <Company>Wiesław Šoltés</Company>
     <Description>A docking layout system.</Description>