diff --git a/deploy/cleanup_bintray.sh b/deploy/cleanup_bintray.sh
new file mode 100755
index 0000000000..482a358e20
--- /dev/null
+++ b/deploy/cleanup_bintray.sh
@@ -0,0 +1,145 @@
+#!/bin/bash
+
+# This file is part of BOINC.
+# http://boinc.berkeley.edu
+# Copyright (C) 2018 University of California
+#
+# BOINC is free software; you can redistribute it and/or modify it
+# under the terms of the GNU Lesser General Public License
+# as published by the Free Software Foundation,
+# either version 3 of the License, or (at your option) any later version.
+#
+# BOINC is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+# See the GNU Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with BOINC.  If not, see <http://www.gnu.org/licenses/>.
+#
+
+## Clean up old files and versions on Bintray (https://bintray.com/docs/api/)
+## Parameters:
+## --weekly_threshold textual representation of the time to keep the weekly builds (default: 6 months, used as argument to date -d)
+## --tmp_dir directory where API responses are stored (default: /tmp)
+
+# be carefull with set -x in this script because of ${BINTRAY_API_KEY} which needs to stay secret
+set -e # Exit on errors
+trap 'exit 1' ERR
+
+# check working directory because the script needs to be called like: ./deploy/cleanup_bintray.sh
+if [ ! -d "deploy" ]; then
+    echo "start this script in the source root directory"
+    exit 1
+fi
+
+ROOTDIR=$(pwd)
+TMPDIR="/tmp"
+weekly_threshold="6 months"
+while [[ $# -gt 0 ]]; do
+    key="$1"
+    case $key in
+        --tmp_dir)
+        TMPDIR="$2"
+        shift
+        ;;
+        --weekly_threshold)
+        weekly_threshold="$2"
+        shift
+        ;;
+        *)
+        echo "unrecognized option $key"
+        ;;
+    esac
+    shift # past argument or value
+done
+
+command -v jq >/dev/null 2>&1 || { echo >&2 "jq (command-line json parser) is needed but not installed.  Aborting."; exit 1; }
+
+# this needs to be set in the environment before starting the script
+if [ "${BINTRAY_API_KEY}" == "" ] ; then
+    echo "BINTRAY_API_KEY is missing; doing nothing"
+    exit 0
+fi
+
+CI_RUN="${TRAVIS:-false}"
+if [[ $CI_RUN == "true" ]]; then
+    echo "This script cannot be used in a CI environment"
+    exit 0
+fi
+
+BINTRAY_API=https://api.bintray.com
+BINTRAY_USER="${BINTRAY_USER:-ChristianBeer}"
+BINTRAY_API_KEY="$BINTRAY_API_KEY" # env
+BINTRAY_REPO="${BINTRAY_REPO:-boinc-ci}"
+BINTRAY_REPO_OWNER="${BINTRAY_REPO_OWNER:-boinc}" # owner and user not always the same
+
+GITHUB_API=https://api.github.com
+GITHUB_USER="${GITHUB_USER:-BOINC}"
+# github has a rate limit of 60 requests per hour for non authenticated requests
+# see https://developer.github.com/v3/#authentication on how to authenticate
+#GITHUB_OAUTH="-H \"Authorization: token OAUTH-TOKEN\""
+GITHUB_OAUTH=""
+GITHUB_REPO="${GITHUB_REPO:-boinc}"
+
+BINTRAY_CURL="curl -s -S -u${BINTRAY_USER}:${BINTRAY_API_KEY} -H Accept:application/json -w \n"
+GITHUB_CURL="curl -s -S ${GITHUB_OAUTH} -H Accept:application/vnd.github.v3+json -w \n"
+
+# get quotas from bintray
+${BINTRAY_CURL} "${BINTRAY_API}/orgs/${BINTRAY_REPO_OWNER}" -o "${TMPDIR}/organisation.txt"
+
+quota_used=$(jq '.quota_used_bytes' < "${TMPDIR}/organisation.txt")
+free_storage=$(jq '.free_storage' < "${TMPDIR}/organisation.txt")
+free_storage_quota_limit=$(jq '.free_storage_quota_limit' < "${TMPDIR}/organisation.txt")
+storage_percent=$(echo "scale=2; $quota_used / $free_storage_quota_limit *100" | bc)
+echo "Storage quota used: ${storage_percent}%"
+
+last_month_download=$(jq '.last_month_free_downloads' < "${TMPDIR}/organisation.txt")
+monthly_download_quota=$(jq '.monthly_free_downloads_quota_limit' < "${TMPDIR}/organisation.txt")
+download_percent=$(echo "scale=2; $last_month_download / $monthly_download_quota *100" | bc)
+echo "Download quota used: ${download_percent}%"
+
+rm -f "${TMPDIR}/organisation.txt"
+
+BINTRAY_PACKAGE="pull-requests"
+echo "Cleaning package: $BINTRAY_PACKAGE"
+
+${BINTRAY_CURL} "${BINTRAY_API}/packages/${BINTRAY_REPO_OWNER}/${BINTRAY_REPO}/${BINTRAY_PACKAGE}" -o "${TMPDIR}/package_pr.txt"
+
+pr_ids=$(jq -r .versions[]? < "${TMPDIR}/package_pr.txt" | cut -d_ -f1 | cut -b 3- | sort -u)
+for pr in $pr_ids
+do
+    echo $pr
+    state=$(${GITHUB_CURL} "${GITHUB_API}/repos/${GITHUB_USER}/${GITHUB_REPO}/pulls/${pr}" | jq -r .state)
+    if [ "$state" = "closed" ]; then
+        echo "  is closed"
+        data="[{\"PR\": [\"${pr}\"]}]"
+        ${BINTRAY_CURL} -H Content-Type:application/json -X POST -d "${data}" "${BINTRAY_API}/search/attributes/${BINTRAY_REPO_OWNER}/${BINTRAY_REPO}/${BINTRAY_PACKAGE}/versions" -o "${TMPDIR}/versions.txt"
+        versions=$(jq -r .[].name < "${TMPDIR}/versions.txt")
+        for version in $versions
+        do
+            echo "Deleting ${version}"
+            ${BINTRAY_CURL} -X DELETE "${BINTRAY_API}/packages/${BINTRAY_REPO_OWNER}/${BINTRAY_REPO}/${BINTRAY_PACKAGE}/versions/${version}"
+        done
+    fi
+done
+
+rm -f "${TMPDIR}/package_pr.txt" "${TMPDIR}/versions.txt"
+echo "Finished cleaning package: $BINTRAY_PACKAGE"
+
+BINTRAY_PACKAGE="weekly"
+echo "Cleaning package: $BINTRAY_PACKAGE"
+
+time_threshold=$(date -u -d "now-${weekly_threshold}" +%s)
+data="[{\"create_time_utc\": \"[,${time_threshold}]\"}]"
+
+${BINTRAY_CURL} -H Content-Type:application/json -X POST -d "${data}" "${BINTRAY_API}/search/attributes/${BINTRAY_REPO_OWNER}/${BINTRAY_REPO}/${BINTRAY_PACKAGE}/versions?attribute_values=1" -o "${TMPDIR}/versions.txt"
+versions=$(jq -r .[].name? < "${TMPDIR}/versions.txt")
+for version in $versions
+do
+    echo "Deleting ${version}"
+    ${BINTRAY_CURL} -X DELETE "${BINTRAY_API}/packages/${BINTRAY_REPO_OWNER}/${BINTRAY_REPO}/${BINTRAY_PACKAGE}/versions/${version}"
+done
+
+rm -f "${TMPDIR}/versions.txt"
+echo "Finished cleaning package: $BINTRAY_PACKAGE"
diff --git a/deploy/deploy_to_bintray.sh b/deploy/deploy_to_bintray.sh
index 343e562f76..b0b21bad56 100755
--- a/deploy/deploy_to_bintray.sh
+++ b/deploy/deploy_to_bintray.sh
@@ -114,9 +114,9 @@ ${CURL} -H Content-Type:application/json -X POST -d "${data}" "${API}/packages/$
 echo "Adding attributes to version ${VERSION}"
 # this can be used to cleanup old versions
 pr="${TRAVIS_PULL_REQUEST:-0}"
-created=$(date -Is)
+created=$(date -u +%s)
 data="[{\"name\": \"PR\", \"values\": [\"${pr}\"], \"type\": \"string\"},
-            {\"name\": \"create_time\", \"values\": [\"${created}\"], \"type\": \"date\"}]"
+            {\"name\": \"create_time_utc\", \"values\": [${created}], \"type\": \"number\"}]"
 echo $data
 ${CURL} -H Content-Type:application/json -X POST -d "${data}" "${API}/packages/${BINTRAY_REPO_OWNER}/${BINTRAY_REPO}/${PKG_NAME}/versions/${VERSION}/attributes"