Thunderbird Android client is K-9 Mail reborn, and it's in solid beta

"Thunderbird's Android app is set to enhance user experience by incorporating K-9 Mail's features, creating a cohesive platform for email management on mobile devices."

"With the acquisition of K-9 Mail, Thunderbird aims to provide robust features like automatic account setup and message filtering, making it more competitive against Gmail and Outlook."

Read at Ars Technica