diff --git a/CURATORS.md b/CURATORS.md
index c6347852..98bbdf64 100644
--- a/CURATORS.md
+++ b/CURATORS.md
@@ -50,7 +50,11 @@ Use [Ubuntu Package content search](http://packages.ubuntu.com/) to determine wh
 ### Upgrading GHC version
 The Dockerfile contains information on which GHC versions should be used. You
 can modify it and push it to Github to trigger a DockerHub build. The master
-branch is used for nightlies, and the lts branch for LTS.
+branch is used for nightlies. For LTSes, we use the ltsX branch, where X is the
+major version number (e.g., lts3 for lts-3.\*).
+
+Note that when starting a new LTS major release, you'll need to modify Docker
+Hub to create a new Docker tag for the relevant branch name.
 
 ### Getting the new image to the build server
 Once a new Docker image is available, you'll need to pull it onto the stackage-build server (see
diff --git a/automated/build.sh b/automated/build.sh
index 8b9ed5cb..0f1d0855 100755
--- a/automated/build.sh
+++ b/automated/build.sh
@@ -4,7 +4,15 @@ set -eux
 
 ROOT=$(cd $(dirname $0) ; pwd)
 TARGET=$1
+
+# For nightly-YYYY-MM-DD, tag should be nightly
+# For lts-X.Y, tag should be ltsX
 TAG=$(echo $TARGET | cut -d- -f 1)
+if [ $TAG = "lts" ]
+then
+    TAG=$(echo $TARGET | sed 's@^lts-\([0-9]*\)\.[0-9]*@lts\1@')
+fi
+
 IMAGE=snoyberg/stackage:$TAG
 
 PLAN_FILE=current-plan.yaml