diff --git a/.github/workflows/python-package.yml b/.github/workflows/python-package.yml
index 9b55df2b..987f133f 100644
--- a/.github/workflows/python-package.yml
+++ b/.github/workflows/python-package.yml
@@ -19,7 +19,7 @@ jobs:
       fail-fast: false
       matrix:
         python-version: ["3.8", "3.9", "3.10", "3.11"]
-        os: ["ubuntu-20.04", "ubuntu-22.04"]
+        os: ["ubuntu-22.04"]
 
     steps:
       - uses: actions/checkout@v2
@@ -37,8 +37,8 @@ jobs:
           sudo apt-get -y update
           sudo apt-get install -y gdal-bin python-tk libgdal-dev libproj-dev libgeos-dev
           python -m pip install --upgrade pip wheel
-          pip install -e .[complete]
           pip install -r test/requirements.txt
+          pip install -e .[complete]
           pip freeze
 
       - name: Lint with flake8
diff --git a/pyproject.toml b/pyproject.toml
index b927524b..49313745 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -50,7 +50,7 @@ complete = [
     "boto3>=1.14.44",
     "dask",
     "distributed",
-    "Flask",
+    "Flask<3.0.0",
     "Flask-RangeRequest",
     "fsspec[http]",
     "fsspec[s3]",
@@ -87,7 +87,7 @@ s3 = [
     "s3fs!=2023.9.0",
 ]
 serve = [
-    "Flask",
+    "Flask<3.0.0",
     "Flask-RangeRequest",
     "werkzeug>=0.15",
 ]
diff --git a/requirements.txt b/requirements.txt
index 1f147371..c57c789e 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -8,7 +8,7 @@ click-plugins>=1.1.1
 click-spinner>=0.1.10
 python-dateutil
 fiona>=1.8.13.post1
-Flask>=1.1.2
+Flask>=1.1.2,<=3.0.0
 Flask-RangeRequest>=0.0.2
 fsspec[s3]>=0.8.4
 geobuf>=1.1.1