diff --git a/translations-app/handleAppTranslations.sh b/translations-app/handleAppTranslations.sh
index debf85b6..2f5c38ff 100755
--- a/translations-app/handleAppTranslations.sh
+++ b/translations-app/handleAppTranslations.sh
@@ -3,6 +3,9 @@
 # verbose and exit on error
 set -xe
 
+# Load the string freeze helpers
+. /stringFreeze.sh
+
 # Print tooling information
 php -v
 tx -v
@@ -74,6 +77,18 @@ if [ -f '.tx/backport' ]; then
   versions="main master $(cat .tx/backport)"
 fi
 
+# During a string freeze no new strings may enter the translation system.
+# This only affects apps that are shipped with the server, all other apps keep
+# syncing their strings. For shipped apps the branch with the new strings is
+# skipped completely and the newest stable branch defines the source strings.
+STRING_FREEZE='false'
+TEMPLATE_BRANCHES='master main'
+if is_string_freeze "$versions" && is_shipped_app "$APP_ID"; then
+  STRING_FREEZE='true'
+  TEMPLATE_BRANCHES=$(newest_stable_branch "$versions")
+  echo "String freeze is active and $APP_ID is shipped: not syncing new strings from main and master, using $TEMPLATE_BRANCHES instead"
+fi
+
 mkdir stable-templates
 mkdir -p translationfiles/templates/
 
@@ -98,6 +113,13 @@ do
     continue
   fi
 
+  if [ "$STRING_FREEZE" = 'true' ] && { [ "$version" = 'master' ] || [ "$version" = 'main' ]; }; then
+    # during the string freeze the new strings of the development branch
+    # must not be added to the translation system
+    echo "Skipping templates of $version during the string freeze"
+    continue
+  fi
+
   cd /app/$version
 
   # build POT files
@@ -119,23 +141,28 @@ done
 cd /app/default
 
 # merge POT files into one
-for file in $(ls stable-templates/master.*)
+# the last branch of the list wins, so main takes precedence over master
+HAS_TEMPLATES='false'
+for template_branch in $TEMPLATE_BRANCHES
 do
-  name=$(echo $file | cut -b 25- )
-  msgcat --use-first stable-templates/*.$name > $SOURCE_FILE
-done
-# alternative merge of main branch
-for file in $(ls stable-templates/main.*)
-do
-  name=$(echo $file | cut -b 23- )
-  msgcat --use-first stable-templates/*.$name > $SOURCE_FILE
+  for file in $(ls stable-templates/$template_branch.* 2>/dev/null)
+  do
+    HAS_TEMPLATES='true'
+    name=${file#stable-templates/$template_branch.}
+    # the template branch comes first, so duplicated strings keep its comments
+    msgcat --use-first $file $(ls stable-templates/*.$name | grep -vxF "$file") > $SOURCE_FILE
+  done
 done
 
 # remove intermediate POT files
 rm -rf stable-templates
 
 # push sources
-tx push -s
+if [ "$HAS_TEMPLATES" = 'true' ]; then
+  tx push -s
+else
+  echo "No source templates found for branch $TEMPLATE_BRANCHES, not pushing sources"
+fi
 
 # pull translations - force pull because a fresh clone has newer time stamps
 tx pull -f -a --minimum-perc=5
diff --git a/translations/Dockerfile b/translations/Dockerfile
index 4f827aad..a0acf09f 100644
--- a/translations/Dockerfile
+++ b/translations/Dockerfile
@@ -42,6 +42,7 @@ RUN mkdir -p /app
 ADD gitconfig /root/.gitconfig
 ADD known_hosts /root/.ssh/known_hosts
 ADD handleTranslations.sh /handleTranslations.sh
+ADD stringFreeze.sh /stringFreeze.sh
 ADD validateTranslationFiles.sh /validateTranslationFiles.sh
 ADD translationtool/translationtool.phar /translationtool.phar
 
diff --git a/translations/handleTranslations.sh b/translations/handleTranslations.sh
index ea71ca3c..479e2bd3 100755
--- a/translations/handleTranslations.sh
+++ b/translations/handleTranslations.sh
@@ -3,6 +3,9 @@
 # verbose and exit on error
 set -xe
 
+# Load the string freeze helpers
+. /stringFreeze.sh
+
 # Print tooling information
 php -v
 tx -v
@@ -31,6 +34,18 @@ git push
 ##################################
 versions='master stable35 stable34 stable33 stable32'
 
+# During a string freeze no new strings may enter the translation system.
+# Everything in the server repository is shipped, so the branch with the new
+# strings is skipped completely and the newest stable branch defines the
+# resources and source strings instead.
+STRING_FREEZE='false'
+TEMPLATE_BRANCH='master'
+if is_string_freeze "$versions"; then
+  STRING_FREEZE='true'
+  TEMPLATE_BRANCH=$(newest_stable_branch "$versions")
+  echo "String freeze is active: not syncing new strings from master, using $TEMPLATE_BRANCH instead"
+fi
+
 mkdir stable-templates
 mkdir -p translationfiles/templates/
 
@@ -55,6 +70,13 @@ do
     continue
   fi
 
+  if [ "$STRING_FREEZE" = 'true' ] && { [ "$version" = 'master' ] || [ "$version" = 'main' ]; }; then
+    # during the string freeze the new strings of the development branch
+    # must not be added to the translation system
+    echo "Skipping templates of $version during the string freeze"
+    continue
+  fi
+
   cd /app/$version
 
   # build POT files
@@ -74,11 +96,13 @@ done
 cd /app/default
 
 # merge POT files into one
-for file in $(ls stable-templates/master.*)
+HAS_TEMPLATES='false'
+for file in $(ls stable-templates/$TEMPLATE_BRANCH.* 2>/dev/null)
 do
-  # Change below to 23 when server switches to main
-  name=$(echo $file | cut -b 25- )
-  msgcat --use-first stable-templates/*.$name > translationfiles/templates/$name
+  HAS_TEMPLATES='true'
+  name=${file#stable-templates/$TEMPLATE_BRANCH.}
+  # the template branch comes first, so duplicated strings keep its comments
+  msgcat --use-first $file $(ls stable-templates/*.$name | grep -vxF "$file") > translationfiles/templates/$name
 done
 
 # remove intermediate POT files
@@ -88,7 +112,11 @@ rm -rf stable-templates
 git checkout master
 
 # push sources
-tx push -s
+if [ "$HAS_TEMPLATES" = 'true' ]; then
+  tx push -s
+else
+  echo "No source templates found for branch $TEMPLATE_BRANCH, not pushing sources"
+fi
 
 # pull translations - force pull because a fresh clone has newer time stamps
 tx pull -f -a --minimum-perc=50
diff --git a/translations/stringFreeze.sh b/translations/stringFreeze.sh
new file mode 100755
index 00000000..613f24ec
--- /dev/null
+++ b/translations/stringFreeze.sh
@@ -0,0 +1,69 @@
+#!/bin/sh
+
+##################################
+# Helpers to handle the translation string freeze
+#
+# Between the first release candidate of a new major Nextcloud release and its
+# final release no new source strings may enter the translation system.
+# The freeze is active while the newest stable branch of nextcloud/server has an
+# OC_VersionString like "35.0.0 RC3". Outside of the freeze the newest stable
+# branch is on a maintenance version like "35.0.4 RC1" or "35.0.3".
+##################################
+
+SERVER_RAW_URL='https://raw.githubusercontent.com/nextcloud/server'
+
+# Print the newest stable branch of a space separated branch list,
+# e.g. "main master stable35 stable33" prints "stable35"
+newest_stable_branch() {
+  FREEZE_MAJOR=$(echo "$1" | tr ' ' '\n' | grep -E '^stable[0-9]+$' | sed -E 's/^stable//' | sort -n | tail -n 1)
+
+  if [ -n "$FREEZE_MAJOR" ]; then
+    echo "stable$FREEZE_MAJOR"
+  fi
+}
+
+# Check whether the string freeze is active, based on the newest stable branch
+# of the given space separated branch list. Returns 0 (true) when it is active.
+is_string_freeze() {
+  FREEZE_BRANCH=$(newest_stable_branch "$1")
+
+  if [ -z "$FREEZE_BRANCH" ]; then
+    echo 'No stable branch in the branch list, so there is no string freeze to respect'
+    return 1
+  fi
+
+  FREEZE_VERSION_PHP=$(curl --silent --show-error --fail --location --retry 3 "$SERVER_RAW_URL/$FREEZE_BRANCH/version.php") || {
+    echo "Could not read version.php of nextcloud/server branch $FREEZE_BRANCH"
+    # Acting like freeze and trying tomorrow again
+    return 0
+  }
+
+  FREEZE_VERSION_STRING=$(echo "$FREEZE_VERSION_PHP" | grep -oE "OC_VersionString *= *'[^']*'" | sed -E "s/.*'(.*)'/\1/")
+  echo "Newest stable branch $FREEZE_BRANCH is at version \"$FREEZE_VERSION_STRING\""
+
+  if [ -z "$FREEZE_VERSION_STRING" ]; then
+    echo "Could not read the OC_VersionString of nextcloud/server branch $FREEZE_BRANCH"
+    # Acting like freeze and trying tomorrow again
+    return 0
+  fi
+
+  case "$FREEZE_VERSION_STRING" in
+    *.0.0\ RC*)
+      return 0
+      ;;
+  esac
+
+  return 1
+}
+
+# Check whether the given app id is shipped with Nextcloud server.
+# Returns 0 (true) when the app is listed in core/shipped.json
+is_shipped_app() {
+  FREEZE_SHIPPED_JSON=$(curl --silent --show-error --fail --location --retry 3 "$SERVER_RAW_URL/master/core/shipped.json") || {
+    echo 'Could not read core/shipped.json of nextcloud/server'
+    # Acting like freeze and trying tomorrow again
+    return 0
+  }
+
+  echo "$FREEZE_SHIPPED_JSON" | jq --exit-status --arg app "$1" '(.shippedApps + .defaultEnabled + .alwaysEnabled) | index($app) != null' > /dev/null
+}