diff --git a/src/GuardClauses/GuardClauses.csproj b/src/GuardClauses/GuardClauses.csproj
index a07b569e..470172a4 100644
--- a/src/GuardClauses/GuardClauses.csproj
+++ b/src/GuardClauses/GuardClauses.csproj
@@ -19,7 +19,7 @@
     Improve support for custom error messages.
     Ensure InvalidFormat doesn't succeed given an empty string and a RegEx requiring at least one character. #161
     </PackageReleaseNotes>
-    <Version>3.3.0</Version>
+    <Version>4.0.0</Version>
     <AssemblyName>Ardalis.GuardClauses</AssemblyName>
     <PackageIcon>icon.png</PackageIcon>
     <PublishRepositoryUrl>true</PublishRepositoryUrl>