diff --git a/.azure-pipelines/templates/jobs/extended-tests-jobs.yml b/.azure-pipelines/templates/jobs/extended-tests-jobs.yml
index 0c92136e8..56e8d447e 100644
--- a/.azure-pipelines/templates/jobs/extended-tests-jobs.yml
+++ b/.azure-pipelines/templates/jobs/extended-tests-jobs.yml
@@ -22,15 +22,19 @@ jobs:
           TOXENV: py37
           CERTBOT_NO_PIN: 1
         linux-boulder-v1-integration-certbot-oldest:
+          PYTHON_VERSION: 3.6
           TOXENV: integration-certbot-oldest
           ACME_SERVER: boulder-v1
         linux-boulder-v2-integration-certbot-oldest:
+          PYTHON_VERSION: 3.6
           TOXENV: integration-certbot-oldest
           ACME_SERVER: boulder-v2
         linux-boulder-v1-integration-nginx-oldest:
+          PYTHON_VERSION: 3.6
           TOXENV: integration-nginx-oldest
           ACME_SERVER: boulder-v1
         linux-boulder-v2-integration-nginx-oldest:
+          PYTHON_VERSION: 3.6
           TOXENV: integration-nginx-oldest
           ACME_SERVER: boulder-v2
         linux-boulder-v1-py27-integration: