I am a third-party developer, let me add additional information on this. Last weeks Blink added 2FA to their application that consists on sending a pin to the registration email to confirm it’s a legitimate access. This new login is done with a new API and the one that third parties are using is the deprecated API on 5/11.
The title of the email is not correct, scripts that upgrade to the new login process will work. In fact, I have updated Bling this morning without major issues. The problem are the scripts/applications that are no longer supported and do not accomodate to the new login process. They mention official IFTTT so they may upgrade before until 5/11.
I have no idea how other scripts/applications work but in case you pass the token to it you may be able to make it work by manually doing the verification process. In case you have accesss to its scripts it’s quite straightforward to add this intermediate verification step.
Take a look at the last commits done in GitHub’s bling-viewer in case you want to update your scripts.