I have a custom plugin that has been working for several months and I am making some updates to it. When I upload the new plugin file via ftp, it uploads properly, I can see the file modification date changed. When I go to the page in wordpress, nothing has changed and the results are from the old plugin code. I have disabled/enabled the plugin, removed the plugin file from the server and replaced it, in both cases the page shows the shortcode while plugin disabled/removed and then goes back to the results of the old code. I have cleared caches on browser, there is no caching plugin in this wordpress install, there is no extra server caching like cloudflare, I have waited 12 hours and tried again...any thoughts? Is plugin code stored in the database and how can I clear that if it is?
For anyone else with this annoying problem:
deactivated and removed plugin from server, moved the plugin file to a new plugin directory folder with a different name, (same plugin name, same shortcode) activated plugin. Now new code being used.
No idea why Wordpress was holding onto the old code, but now I don't care because my problem is solved. Actually I do care, but I can't spend any more time on this now that it is "fixed".