diff --git a/.github/workflows/nightly.yaml b/.github/workflows/nightly.yaml
index 74e695fa5..f79d07617 100644
--- a/.github/workflows/nightly.yaml
+++ b/.github/workflows/nightly.yaml
@@ -11,7 +11,7 @@ on:
   - cron: "0 5 * * *"
 
 env:
-  GAMS_VERSION: 25.1.1
+  GAMS_VERSION: 29.1.0
   # See description in lint.yml
   depth: 100
 
diff --git a/.github/workflows/pytest.yaml b/.github/workflows/pytest.yaml
index bcbd9e25d..d0206d264 100644
--- a/.github/workflows/pytest.yaml
+++ b/.github/workflows/pytest.yaml
@@ -13,7 +13,7 @@ concurrency:
   cancel-in-progress: true
 
 env:
-  GAMS_VERSION: 25.1.1
+  GAMS_VERSION: 29.1.0
   # See description in lint.yml
   depth: 100
 
@@ -76,7 +76,7 @@ jobs:
     - uses: iiasa/actions/setup-gams@main
       with:
         version: ${{ env.GAMS_VERSION }}
-        license: ${{ secrets.GAMS_LICENSE }}
+        # license: ${{ secrets.GAMS_LICENSE }}
 
     - name: Install Python package and dependencies
       # By default, the below installs ixmp from the main branch. To run against
@@ -160,7 +160,7 @@ jobs:
     - uses: iiasa/actions/setup-gams@main
       with:
         version: ${{ env.GAMS_VERSION }}
-        license: ${{ secrets.GAMS_LICENSE }}
+        # license: ${{ secrets.GAMS_LICENSE }}
 
     - name: Install Python package and dependencies
       # By default, the below installs ixmp from the main branch. To run against