diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index bfe9802..a215d3a 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -6,7 +6,7 @@ jobs:
     strategy:
       matrix:
         os: [ ubuntu-latest, macos-latest, windows-latest ]
-        go: [ 1.22.x ]
+        go: [ 1.21.x, 1.22.x ]
     env:
       OS: ${{ matrix.os }}
       GO: ${{ matrix.go }}
diff --git a/go.mod b/go.mod
index bd8cb11..57bd939 100644
--- a/go.mod
+++ b/go.mod
@@ -1,3 +1,3 @@
-module github.com/open-spaced-repetition/go-fsrs
+module github.com/open-spaced-repetition/go-fsrs/v2
 
-go 1.22
+go 1.21