Can't install Android build versions?

[Wombat97]

Really sorry if this has been asked already but I managed to download the latest build off orphis and tried to apply the update to the existing ppsspp app but I get an error saying an existing package with same name and conflicting signature was already installed.

I get that it probably means I would need to uninstall my current google play version but will that delete my save files and states or just the app itself?

I only ask because in some instructions this detail is not mentioned, instead just saying that a message would ask if you wanted to update ppsspp or not?