Error in en-GB.com_osmembership.ini in 2.8v

I encounter an error "OSM_INVALID_UPGRADE_MEMBERSHIP_OPTION" in message system.
And after further investigation in en-GB.com_osmembership.ini, I find out that this info is missed from .ini file.

So, Is one other file that contains info for this tag or is missed for some reason?
If it's missed, what info I have to add to eliminate this error in Membership Pro Message system?
I'm using the 2.8 version on J 3.6.5.

Thanks for your support.
Mark

Hello Mark

The is was missing from language file. You can add it to the end of language file for now

OSM_INVALID_UPGRADE_MEMBERSHIP_OPTION="Invalid upgrade option"

I will add it to the language file for the next release

Regards,

Tuan