[Arizhel]

The problem is that there aren't exactly a lot of other great FOSS standalone email applications these days. Everything's been neglected because of webmail, and corporations' dogged insistence on Outlook.

So if you think Thunderbird should be killed, what do you suggest as a replacement? It needs to be free, and run on Windows for my company to use it.

[st3fan]

Not free, but Postbox is pretty great. It is a continuation of Thunderbird. By former Thunderbird engineers if I am not mistaken.

https://www.postbox-inc.com/

[asymmetric]

Might be pretty great but it's Windows/macOS only, so not sure how much of a continuation of thunderbird it can be considered.

[diegoprzl]

Claws Mail is a good option.

[jhasse]

If you're using Linux, try Geary.