diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index dc6ee562..b35b811f 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -20,7 +20,7 @@ jobs:
   unit-tests:
     runs-on: ubuntu-20.04
     strategy:
-      max-parallel: 4
+      max-parallel: 3
       matrix:
         python-version: ["3.8", "3.9", "3.10"]
     steps:
@@ -96,7 +96,7 @@ jobs:
     needs: [build]
     runs-on: ubuntu-20.04
     strategy:
-      max-parallel: 4
+      max-parallel: 3
       matrix:
         python-version: ["3.8", "3.9", "3.10"]
     steps:
diff --git a/tox.ini b/tox.ini
index c7ac080c..e978f3a1 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,6 +1,6 @@
 [tox]
 isolated_build = true
-envlist = py{37,38,39,310},mot-py39
+envlist = py{38,39,310},mot-py39
 
 [testenv]
 allowlist_externals = poetry
@@ -12,10 +12,10 @@ commands =
     poetry install --no-root --only=test -v
     poetry run pytest -s tests/
 
-[testenv:py{37,38,39,310}]
+[testenv:py{38,39,310}]
 description = run unit tests
 
-[testenv:mot-py{37,38,39,310}]
+[testenv:mot-py{38,39,310}]
 description = compute MOT metrics for evaluation
 extras = metrics
 commands =