diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index ec0a901..3ea651c 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -8,22 +8,22 @@ on:
 jobs:
   pre-commit:
     name: Lint
-    runs-on: ubuntu-18.04
+    runs-on: ubuntu-latest
     steps:
       - name: Cancel Previous Runs
-        uses: styfle/cancel-workflow-action@0.6.0
+        uses: styfle/cancel-workflow-action@0.12.0
         with:
           access_token: ${{ github.token }}
-      - uses: actions/checkout@v2
-      - uses: actions/setup-python@v2
-      - uses: pre-commit/action@v2.0.0
+      - uses: actions/checkout@v4
+      - uses: actions/setup-python@v4
+      - uses: pre-commit/action@v3.0.0
 
   test:
     name: Python
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
-        python: [ 3.7, 3.9 ]
+        python: [ 3.8, 3.11 ]
         os:  [ macos-latest, ubuntu-latest, windows-latest ]
     defaults:
       run:
@@ -59,7 +59,6 @@ jobs:
           channels: conda-forge
           channel-priority: strict
           auto-update-conda: true
-          use-only-tar-bz2: true
 
       - name: Fix windows .profile
         if: steps.cache.outputs.cache-hit != 'true' && matrix.os == 'windows-latest'
@@ -69,7 +68,9 @@ jobs:
       - name: Install conda deps
         if: steps.cache.outputs.cache-hit != 'true'
         shell: bash -l {0} #We need a login shell to get conda
-        run: conda install --yes --file=requirements/CI-tests-conda.txt
+        run: |
+          conda install mamba
+          mamba install --yes --file=requirements/CI-tests-conda.txt
 
       - name: Fix OSX Cache Write #OSX Won't let the cache restore due to file perms
         if: steps.cache.outputs.cache-hit != 'true' && matrix.os == 'macos-latest'
diff --git a/.mergify.yml b/.mergify.yml
index 2408c9b..018c8fa 100644
--- a/.mergify.yml
+++ b/.mergify.yml
@@ -31,7 +31,6 @@ pull_request_rules:
       queue:
         name: default
         method: rebase
-        rebase_fallback: none
         update_method: rebase
 
   - name: Remove label after merge
diff --git a/requirements/CI-tests-conda.txt b/requirements/CI-tests-conda.txt
index d7b6155..181c40c 100644
--- a/requirements/CI-tests-conda.txt
+++ b/requirements/CI-tests-conda.txt
@@ -1,5 +1,5 @@
 humanize==4.8.0
-h5py<3.2
+h5py==3.7.0
 msprime==1.2.0
 pytest==7.4.2
 pytest-cov==4.1.0