diff --git a/CHANGELOG.md b/CHANGELOG.md
index 5060f655..e3efb333 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,10 @@ All notable changes to this project will be documented in this file
 automatically by Versionist. DO NOT EDIT THIS FILE MANUALLY!
 This project adheres to [Semantic Versioning](http://semver.org/).
 
+## v6.6.5 - 2018-02-21
+
+* Circle.yml: escape branch name to ensure we always have a valid tag #556 [Pablo Carranza Velez]
+
 ## v6.6.4 - 2018-02-20
 
 * Circle.yml: Do not push images to dockerhub if building without a docker password #555 [Pablo Carranza Velez]
diff --git a/circle.yml b/circle.yml
index fdb8bf3a..4ae9284e 100644
--- a/circle.yml
+++ b/circle.yml
@@ -48,7 +48,7 @@ defaults: &defaults
               export PUSH_IMAGES=false
             fi
             # start the build for this architecture
-            export TAG=${CIRCLE_BRANCH}
+            export TAG=$(echo ${CIRCLE_BRANCH} | sed 's/[^a-z0-9A-Z_.-]/-/g')
             export ARCH=${ARCH}
             bash automation/build.sh
             if [ "${CIRCLE_BRANCH}" = "master" ] && [ "${DEPLOY_TO_RESIN}" = "true" ]; then
diff --git a/package.json b/package.json
index 24a282ad..e5e83c7c 100644
--- a/package.json
+++ b/package.json
@@ -1,7 +1,7 @@
 {
   "name": "resin-supervisor",
   "description": "This is resin.io's Supervisor, a program that runs on IoT devices and has the task of running user Apps (which are Docker containers), and updating them as Resin's API informs it to.",
-  "version": "6.6.4",
+  "version": "6.6.5",
   "license": "Apache-2.0",
   "repository": {
     "type": "git",