The upgrade of plugin process needs to be re-examined. To update a simple plugin like, 0xArt Advanced SEO, shouldn't break the site.
I can see clearly now that I should have fully uninstalled it. The download latest version and re-install, which is OK for a plugin that doesn't lose any info if its fully uninstalled, but for other plugins that will lose data, you can't take that approach.
I had 30,000 visitors last month, which gives you an indication of how big a problem this for me. This is a continuous problem and costly. While feel Oxwall has many advantages over other systems, I would NOT recommend to anyone else and wont until these issues with the upgrade process are addressed.
What a disappointment. Something really needs to be done. I lose so much time fixing these things.