1.5.5.0 upgrade issue

[PeteZ]

trying to upgrade 1.5.5.0 but i get a 500 error. when i click on 1 click update configure button

I think it could be maybe a php server version issue with this older cart?
I see this error in the setting check area
Optional parameters: Please fix the following error(s)
mbstring

Maybe this is an issue because of later php version on server.


Also I see this
Missing files (1)
admin9523/autoupgrade/index.php
replaced that file but when I attempt again it adds different files and folder in there.
Maybe I should install earlier version of 1 click upgrade?

[PeteZ]

its ok. Hopefully I have an install specialsit looking at it.