When switch to https done is it safe to delete plugin?

If you need the mixed content fixer or the wp redirect, you need to have it activated.

If you have activated .htaccess redirect, and do not have any mixed content without the plugin, you could remove it. But do not deactivate: that will revert your site to http. Just delete it through FTP.

Thanks for your fast reply.

I just reported another issue and the deactivation explains that home/URL was http, in my assumption after conversion, but it is by deactivating your plugin.

I guess it would be better not to revert back to http when deactivating plugin?

I understand the confusion, but as most people need the mixed content fixer, it is usually not deactivated. In most cases, when users want to deactivate, they do this because they have issues on SSL. They expect to return to http after the deactivation, which is why it has ben designed this way.

The advantage is, users can easily revert their site to http if needed.