diff --git a/.github/workflows/tomophantom_conda_upload.yml b/.github/workflows/tomophantom_conda_upload.yml
index 7ff4c74..6091c43 100644
--- a/.github/workflows/tomophantom_conda_upload.yml
+++ b/.github/workflows/tomophantom_conda_upload.yml
@@ -14,7 +14,7 @@ jobs:
       - name: Checkout repository code
         uses: actions/checkout@v3
         with:
-          ref: "main"
+          ref: "master"
           fetch-depth: 0
 
       # setup Python 3.9