Rated 4 out of 5 stars

I use it for years and appreciate it but since thunderbird 78 I've got an error "Incompatibility between send it later and enigmail" and even if I chose "no encryption" and "signed" my message is encrypted if I want to "send it later".
So I can't "send later" signed message. Or I send later, or I sign (and encrypt)
Dispite that, I love your plug in and hope you will fix it soon !

This review is for a previous version of the add-on (8.6.5). 

This is a problem with the way Thunderbird handles encryption now that Enigmail is built into the client. There is no longer a mechanism for turning off "encrypt draft messages" as there used to be. There is nothing Send Later can do about this unfortunately. See here for more details: https://github.com/Extended-Thunder/send-later/discussions/200