
Policies.json: "PostMessage" signature fails on Thunderbird 140 ESR, but other policies work
Hello, I'm trying to deploy a dynamic HTML signature on Thunderbird 140 ESR using policies.json. The goal is to pull user data (full name, job title, phone number) from our Active Directory.
The PostMessage policy for setting the signature is completely ignored. However, other policies like DisableAppUpdate work perfectly, so I know policies.json is being read correctly.
Troubleshooting has confirmed this is not a path or permission issue, as the signature also fails when using a local file (file:///C:/...) and even when the signature is set as direct text inside the policy itself.
Is this a known bug or issue in v140 ESR? Is there a reliable method to deploy a dynamic signature from AD via policy?
Thank you.