Blacklist android app

Is the blacklist of the androidapp synced with the windows app ?

No, there is currently no 2-ways sync between mobile and desktop app. However we plan to support server side blacklist sync for some servers that supports that feature, which will resolve that for these accounts.

What do you mean by “some servers” ?
My mail accounts are all imap accounts.

IMAP itself has no specification for that. It is a proprietary feature of some mail servers. Currently we plan to support this for SmarterMail servers. Most IMAP servers don’t support that.