--- a/testing/docker/recipes/install-mercurial.sh
+++ b/testing/docker/recipes/install-mercurial.sh
@@ -8,32 +8,32 @@
 set -e
 
 # Detect OS.
 if [ -f /etc/lsb-release ]; then
     . /etc/lsb-release
 
     if [ "${DISTRIB_ID}" = "Ubuntu" -a "${DISTRIB_RELEASE}" = "16.04" ]; then
         HG_DEB=1
-        HG_DIGEST=7b1fc1217e0dcaeea852b0af2dc559b1aafb704fbee7e29cbec75af57bacb84910a7ec92b5c33f04ee98f23b3a57f1fa451173fe7c8a96f58faefe319dc7dde1
-        HG_SIZE=44878
-        HG_FILENAME=mercurial_3.8.4_amd64.deb
+        HG_DIGEST=09c7c80324158b755c23855d47caeb40b953218b1c89c7f5f21bbdea9de1d13a7ed5a7e647022ff626fb9674655baf05f6965361ccef3fa82b94d1fa8a684187
+        HG_SIZE=44956
+        HG_FILENAME=mercurial_3.9.1_amd64.deb
 
-        HG_COMMON_DIGEST=b476e2612e7495a1c7c5adfd84511aa7479e26cc9070289513ec705fbfc4c61806ce2dbcceca0e63f2e80669be416f3467a3cebb522dcb8a6aeb62cdd3df82f2
-        HG_COMMON_SIZE=1818422
-        HG_COMMON_FILENAME=mercurial-common_3.8.4_all.deb
+        HG_COMMON_DIGEST=ef281d1368a8cf2363bc08c050aff3825028ba4d47d491e50e10f4c78574d5e87231a0096c7d9cb3439dd4b5172057a050e02946b4cf8b2bdf239ffd50a85d06
+        HG_COMMON_SIZE=1847796
+        HG_COMMON_FILENAME=mercurial-common_3.9.1_all.deb
     elif [ "${DISTRIB_ID}" = "Ubuntu" -a "${DISTRIB_RELEASE}" = "12.04" ]; then
         HG_DEB=1
-        HG_DIGEST=96366b6baac26017a2ef9cd0bbbba4f18756e02921b0ff3541f677484d53d2041f01202b743ea8cdb96db58e88317da18befefc9711a085b054f9abc3dad1679
-        HG_SIZE=54992
-        HG_FILENAME=mercurial_3.8.4_amd64.deb
+        HG_DIGEST=f816a6ca91129c0723527d98a2978c253a3f941f4358f9f8abd6f3ab8e8601ed3efc347828aac8f0d0762f819f9b777299e31037c39eb0c5af05aa76ac25c3bf
+        HG_SIZE=55144
+        HG_FILENAME=mercurial_3.9.1_amd64.deb
 
-        HG_COMMON_SIZE=2946616
-        HG_COMMON_DIGEST=96c6bc305ae85f16885d0b6ac6800361d680811346a01338a56a2174a3c0ae5d86bbd827d93fe8c59d71acd2e1cc7d6e79e39a179836d5695cbfa3b370982ee5
-        HG_COMMON_FILENAME=mercurial-common_3.8.4_all.deb
+        HG_COMMON_DIGEST=ac2b2fab9f19438c77147dca8df5020d10b129052e6c5f77ebe9a4c21eb0cedb1acfe25b146577bf5e9b66f3d6cfca2474f7575adfba1b3849b66bf5bc321015
+        HG_COMMON_SIZE=2993590
+        HG_COMMON_FILENAME=mercurial-common_3.9.4_all.deb
     fi
 fi
 
 if [ -n "${HG_DEB}" ]; then
 tooltool_fetch <<EOF
 [
 {
     "size": ${HG_SIZE},