1.0 The upgraded tag does not appear in the Ruuvi Station App.
2.0 It does still show up in the nRF connect ap on the iPhone. As a physical web/eddystone device
3.0 I can see it with the iPhone NFC reader and tell the the upgrade has completed
4.0 These were part of the original kickstarter funding so the are quite old (still working mostly fine!)
5.0 Be warned its been several years since I played with them, I’m a tad rusty.
I think you have several RuuviTags, with one broadcasting Eddystone data and the one you have scanned with NFC being another one. The 2.5.9 doesn’t support Eddystone broadcasts at all, so it must be some other tag