--- a/create-test-environment
+++ b/create-test-environment
@@ -176,17 +176,17 @@ fi
 hg -R venv/hg pull
 
 mercurials=`pwd`/venv/mercurials
 
 for old in 3.0 3.0.1 3.0.2 3.1 3.1.1 3.1.2 3.2 3.2.1 3.2.2 3.2.3 3.2.4 3.3 3.3.2 3.3.3 3.4 3.4.1 3.4.2 3.5 3.5.1 3.5.2 3.6 3.6.2 3.7.1 3.7.3; do
   rm -rf $mercurials/$old
 done
 
-for v in 3.8.4 3.9.2; do
+for v in 3.8.4 3.9.2 4.0.2; do
   destdir=$mercurials/$v
   if [ ! -d $destdir ]; then
     cd venv/hg
     hg up $v
     # We don't care about support files, which only slow us down, so
     # install-bin is the only target we need.
     make install-bin PREFIX=$destdir
     hg --config extensions.purge= purge --all

--- a/deploy-requirements.txt
+++ b/deploy-requirements.txt
@@ -29,18 +29,18 @@ jmespath==0.9.0 \
     --hash=sha256:ade5261b0d7d34b6f53accc91e6881b579b40161ed575e6ac465de5edad32815
 
 mach==0.5.1 \
     --hash=sha256:61bda1a1033c110f781427c479dd151a45fc45e46ce28e37fabf0d3cc2edf91e
 
 MarkupSafe==0.23 \
     --hash=sha256:a4ec1aff59b95a14b45eb2e23761a0179e98319da5a7eb76b56ea8cdc7b871c3
 
-Mercurial==4.0.1 \
-    --hash=sha256:6aa4ade93c1b5e11937820880a466ebf1c824086d443cd799fc46e2617250d40
+Mercurial==4.1.2 \
+    --hash=sha256:09415253fb409a77e19b9951532a3c22c4e07e74bab80652527064617daab194
 
 mozfile==1.1 \
     --hash=sha256:e1d8505c9d575051e0831ee659a982a2bbfaec37013dc946d60a3071a442888e
 
 mozinfo==0.7 \
     --hash=sha256:d27f75b668614f28df2e61b8aa4beb6f68f3c9936fc9139fae755728f2b4844a
 
 mozprocess==0.22 \