Version 1.2 of ChangeTheHeaders, my new Safari extension to customize HTTP request headers, is available now in the App Store. I just released version 1.0 last week, but unfortunately it had a few bugs. Version 1.1 already fixed a couple of bugs, and now version 1.2 fixes another bug: the error "Invalid call to declarativeNetRequest.updateDynamicRules()" could not be dismissed when you opened the ChangeTheHeaders popup. Sorry about that!