Rated 4 out of 5 stars

Good and useful add-on.To get the 5th star ;-) just one little suggestion :When I send a mail without subject, ThunderBird asks "without subject ? Are you sure ?". Then the panel of "Send Later" appears and if I answser "send now", Thunderbird asks A SECOND TIME "without subject ? Are you sure ?"It's a little ...boring.Another remark :In general options, I chose "replace send button by send later button", but the button remains "send"Yet, in an older version, it was ok....Thank You !(Send Later v 4.1.4 (french version) with ThunderBird v 16.0.2).


Reply to jikamens (Nov 17) :
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I found my button with the label "send later" in this new version also :
It's when you customize the toolbar of "new message" window. You can even have others buttons with labels "15 mn later" , "2 hours later" ...
In the end, the use is easier than to check the option "'replace send button by send later button'.

This review is for a previous version of the add-on (4.1.4). 

"When I send a mail without subject, Thunderbird asks 'without subject ? Are you sure ?'. Then the panel of 'Send Later' appears and if I answer 'send now', Thunderbird asks A SECOND TIME 'without subject ? Are you sure ?'"

Unfortunately, the architecture of Thunderbird and how Send Later integrates with it makes it impossible for me to fix this. I don't mean to be snarky, but a reasonable work around is "Don't do that." There's a reason why Thunderbird discourages you from sending messages with empty Subject lines, after all...

"In general options, I chose 'replace send button by send later button', but the button remains 'send'
Yet, in an older version, it was ok...."

I'm not sure what you mean about it being ok in an older version. There has _never_ in Send Later been an option to replace the Send button with a button that says "Send Later". What that preference does is causes the Send button to _behave_ like "Send Later", i.e., it causes the Send Later window to pop up, but the label on the button does not change and never has.