After asking [this question](https://softwarerecs.stackexchange.com/questions/50605/android-email-client-similar-to-thunderbird) it looked like K9 was the answer for me. Now I see that there is no Windows version of K9, so here's the same question again, but for Windows & Android, the same client for both, please. I use Thunderbird as my Windows desktop email client. There is no Thunderbird for Android. I actually quite like the Gmail client, but do not want Google reading all of my mail. I need something which : - will handle multiple accounts (at least a dozen), and keep them separate - has good search capabilities (message body too, not just header) partial sender address, wildcard searches, date range searches, all of these combinable - a bunch of plugins would be nice - I especially want GPG support - and I don't want it scanning my emails & using me as "the product" - has IMAP support - allows me to schedule how often it checks for new mail (not once an hour, like Gmail) - supports common mailbox formats, so that I could switch to a new client & import - tags are nice - mark as "in need of reply" & remind me I don't need a calendar or fancy address book, but won't object. Low resource usage would be nice. Stable, with good support & an active user community. Gratis (and add-free) would be great, but I am willing to pay, if there is a compelling reason. I don't need open source, but don't object to it.