During the N800’s active life, users accessed Facebook chat/Messages via:
Let’s address the elephant in the room: There was never an official, verified Facebook Messenger client for the Nokia N800.
Why?
So why do people search for a "verified" version? They are looking for a trusted, malware-free method to connect to Facebook’s legacy XMPP gateway.
From Internet Tablet Talk forums (circa 2010): facebook messenger for nokia n800 verified
“I use Pidgin on my N800 with Facebook XMPP. Works fine for simple messages. No video or voice, but the browser can load m.facebook.com for the rest.”
— poster ‘tmo_fan’, June 2011
“After Facebook killed XMPP in 2014, my N800 became useless for Messenger. Browser says ‘You need a newer browser.’”
— poster ‘old_tablet_guy’, May 2014 During the N800’s active life, users accessed Facebook
Why “Verified” was critical: In 2009, Facebook changed its SSL certs. Many N800 users faced a "Certificate not verified" error. A forum user named "BenedictG" on Talk.maemo.org released a package called fb-certs-fix.deb. This was the closest thing to a "verified messenger."