Can I update v16 to v25 directly? or should i update to each version

[yangzepa]

currently i have unrooted v16 version.
i tried to update to v25 version with using the file on official support page.
but after i rebooted into recovery mode, I cannot find the menu named
' Install custom OS on your COSMO ', there is 'Apply update from SD Card' instead.
[it does not work anyway]

in this case, what should I do with this firmware?
ive found manual update method with v23 or v22,
should I do manual update to 22 or 23 and update v25 after?

[yangzepa]

also self-answered, thru all the way around. thanks to many forum posts.

- TRWP used to upgrade to v19 (https://www.oesf.org/forum/index.php?topic=36448.msg297113#msg297113)
- update to v23 via official support page (https://support.planetcom.co.uk/index.php/Cosmo_Android_Firmware_Manual_Installation)
- update to v25 via official support page (https://support.planetcom.co.uk/index.php/Rooted_Android_For_Cosmo)

currently working on CoDi firmware.