diff --git a/RELEASE_NOTES.md b/RELEASE_NOTES.md
index 5c7b09aab9..c1f5cf4e4a 100644
--- a/RELEASE_NOTES.md
+++ b/RELEASE_NOTES.md
@@ -1,3 +1,6 @@
+#### 2.27.11 - 24.11.2015
+* BUGFIX: Specifying prereleases did not work with pessimistic version constraint - https://github.com/fsprojects/Paket/issues/1252
+
 #### 2.27.10 - 23.11.2015
 * Create installer demo - https://github.com/fsprojects/Paket/issues/1251
 
diff --git a/src/Paket.Core/VersionRange.fs b/src/Paket.Core/VersionRange.fs
index 13d142dab0..7006fb8bf1 100644
--- a/src/Paket.Core/VersionRange.fs
+++ b/src/Paket.Core/VersionRange.fs
@@ -109,7 +109,7 @@ type VersionRequirement =
                 | VersionRangeBound.Including -> version >= from
                 | VersionRangeBound.Excluding -> version > from
 
-            isInLowerBound && isInUpperBound  && checkPrerelease prerelease version
+            (isInLowerBound && isInUpperBound && checkPrerelease prerelease version) || sameVersionWithoutPreRelease from
 
     member this.Range =
         match this with
diff --git a/tests/Paket.Tests/DependenciesFile/VersionRangeSpecs.fs b/tests/Paket.Tests/DependenciesFile/VersionRangeSpecs.fs
index e3b17e701c..57f643a754 100644
--- a/tests/Paket.Tests/DependenciesFile/VersionRangeSpecs.fs
+++ b/tests/Paket.Tests/DependenciesFile/VersionRangeSpecs.fs
@@ -22,7 +22,7 @@ let ``can detect specific version``() =
 [<Test>]
 let ``can detect ordinary Between``() = 
     parseRange "~> 2.2" |> shouldEqual (VersionRange.Between("2.2","3.0"))
-    parseRange "~> 1.2" |> shouldEqual (VersionRange.Between("1.2","2.0"))        
+    parseRange "~> 1.2" |> shouldEqual (VersionRange.Between("1.2","2.0"))
     (VersionRequirement(parseRange "~> 1.0",PreReleaseStatus.All)).IsInRange(SemVer.Parse("1.0.071.9556")) |> shouldEqual true
     (VersionRequirement(parseRange "~> 1.0",PreReleaseStatus.All)).IsInRange(SemVer.Parse("1.0.071.9432")) |> shouldEqual true
 
@@ -30,7 +30,7 @@ let ``can detect ordinary Between``() =
 let ``can detect lower versions for ~>``() = 
     parseRange "~> 3.2.0.0" |> shouldEqual (VersionRange.Between("3.2.0.0","3.2.1.0"))
 
-    parseRange "~> 1.2.3.4" |> shouldEqual (VersionRange.Between("1.2.3.4","1.2.4.0"))    
+    parseRange "~> 1.2.3.4" |> shouldEqual (VersionRange.Between("1.2.3.4","1.2.4.0"))
     parseRange "~> 1.2.3" |> shouldEqual (VersionRange.Between("1.2.3","1.3.0"))
     parseRange "~> 1.2" |> shouldEqual (VersionRange.Between("1.2","2.0"))
     parseRange "~> 1.0" |> shouldEqual (VersionRange.Between("1.0","2.0"))
@@ -80,7 +80,7 @@ let ``can detect prereleases``() =
 
 [<Test>]
 let ``can detect override operator``() = 
-    parseRange "== 3.2.0.0" |> shouldEqual (VersionRange.OverrideAll(SemVer.Parse "3.2.0.0"))    
+    parseRange "== 3.2.0.0" |> shouldEqual (VersionRange.OverrideAll(SemVer.Parse "3.2.0.0"))
 
 [<Test>]
 let ``can detect override operator for beta``() = 
diff --git a/tests/Paket.Tests/DependenciesFile/VersionRequirementSpecs.fs b/tests/Paket.Tests/DependenciesFile/VersionRequirementSpecs.fs
index 8dcb9cc90b..afb22cf8c4 100644
--- a/tests/Paket.Tests/DependenciesFile/VersionRequirementSpecs.fs
+++ b/tests/Paket.Tests/DependenciesFile/VersionRequirementSpecs.fs
@@ -1,4 +1,4 @@
-module paket.dependenciesFile.VersionRequirementSpecs
+module Paket.DependenciesFile.VersionRequirementSpecs
 
 open Paket
 open NUnit.Framework
diff --git a/tests/Paket.Tests/FilterVersionSpecs.fs b/tests/Paket.Tests/FilterVersionSpecs.fs
index 19c099943e..f769612310 100644
--- a/tests/Paket.Tests/FilterVersionSpecs.fs
+++ b/tests/Paket.Tests/FilterVersionSpecs.fs
@@ -76,6 +76,11 @@ let ``can check if in range for 4-parts range``() =
     "1.0.0.3108" |> isInRange (DependenciesFileParser.parseVersionRequirement "1.0.0.3108") |> shouldEqual true
     "1.0.0.2420" |> isInRange (DependenciesFileParser.parseVersionRequirement "~> 1.0") |> shouldEqual true
 
+[<Test>]
+let ``does include prerelease when twiddle wakka``() =
+    "1.0.0-alpha002" |> isInRange (DependenciesFileParser.parseVersionRequirement "~> 1.0 alpha") |> shouldEqual true
+    "1.0" |> isInRange (DependenciesFileParser.parseVersionRequirement "~> 1.0 alpha") |> shouldEqual true
+
 [<Test>]
 let ``can support trailing 0``() =
     "1.2.3" |> isInRange (DependenciesFileParser.parseVersionRequirement "1.2.3.0") |> shouldEqual true
diff --git a/tests/Paket.Tests/UpdateProcessSpecs.fs b/tests/Paket.Tests/UpdateProcessSpecs.fs
index c7ac7d0278..d333a01a6d 100644
--- a/tests/Paket.Tests/UpdateProcessSpecs.fs
+++ b/tests/Paket.Tests/UpdateProcessSpecs.fs
@@ -734,7 +734,7 @@ let ``SelectiveUpdate updates package that conflicts with transitive dependency
     let expected = 
         [("Ninject.Extensions.Interception","0.0.2-alpha001");
         ("Ninject.Extensions.Logging","0.0.3");
-        ("Ninject", "0.0.3-alpha001")]
+        ("Ninject", "0.0.2-alpha001")]
         |> Seq.sortBy fst
 
     result