Where did you hear this? That's not true, and in fact I have a number of old-style extensions I develop that work just fine in Thunderbird 60+. However, add-ons will likely need some small updates for TB 60, so they've been marked as incompatible by default.
> Thunderbird 60 drops .xpi support
Where did you hear this? That's not true, and in fact I have a number of old-style extensions I develop that work just fine in Thunderbird 60+. However, add-ons will likely need some small updates for TB 60, so they've been marked as incompatible by default.