It's not a "proper" abbreviation in the sense of "commonly used". I don't think there is one for vorheriger. Same is true for Install. as an abbreviation for Installation.

I see how these came to be. The German translation is obviously much longer than the English text, there probably wasn't enough space on the UI, so they made up abbreviations that were as unambiguous as possible while just fitting the space. I have done similar things.

As Janka states in a comment, voriger would have been a good/better alternative (if the last installation is what is meant). The abbreviation vorh. is ambiguous, I would normally understand it to mean vorhanden.

It's not a "proper" abbreviation in the sense of "commonly used". I don't think there is one for vorheriger. Same is true for Install. as an abbreviation for Installation.

I see how these came to be. The German translation is obviously much longer than the English text, there probably wasn't enough space on the UI, so they made up abbreviations that were as unambiguous as possible while just fitting the space. I have done similar things.

As Janka states in a comment, voriger would have been a good/better alternative (if the previous installation is what is meant). The abbreviation vorh. is ambiguous, I would normally understand it to mean vorhanden.