Hi. I usually update plugins on my sites by searching for the plugin name in the Manage Plugins screen, then I just tick the box to select all sites that have that plugin installed and then MainWP allows me to bulk upload a new version to the checked websites.
But I noticed that I can’t do this with a theme. When searching via the Manage Themes screen, MainWP shows the websites that have that theme installed but I can’t select them as there is a padlock icon (indicating that the theme is active). I understand this is to prevent accidentally deleting an active theme but then I can’t upload a new version via this method. This search is needed because not all websites are using the same theme.
One workaround I found is to hover my mouse over each website, note the ID number of it, then write it down in Notepad formatted as such:
&selected-sites=2-4-5-9-10-(etc)
After that I go to the url /wp-admin/admin.php?page=ThemesInstall and append the string I wrote above. With this the Install Themes screen will open with all those sites already checked, just like with the Install Plugins screen does after a search.