Sending reminders via e-mail has been reenabled in 2020.08.0 and I would like to share my experience struggling to set it up for Gmail.
In TB Settings | Reminders set up Gmail like you normally would. Most fields will be prefilled for you. Do not fill the Gmail account password (or do, and find out that the 'check connection' button returns an error). Leave that window open.
Make sure to read the release notes here https://www.theocbase.net/theocbase-news/version2020-08-01.html and follow the instructions on the Google page referred to in that post.
If 2-step authentication hasn't already been set up, you need to do that first. Once that is done, Security settings (the menu item Security is almost impossible to find unless you use a maximised browser window) will have a new option available under Signing in to Google, which is: Set App Passwords. Enter that option.
Click the dropdown arrow next to app and choose "Other (custom name)" in which case the 'device' selection will disappear. Enter 'TheocBase' (without the quotation marks) as the name of the app you want to create a password for, and click Generate. A 16 character password will appear on yellow background.
From this point it got hazy for me, for TB does not prompt for an extra password, does it? The answer is this password replaces your own Gmail password in TB.
So enter the 16 character password, without spaces, into the password field on the TB settings page, replacing your actual Gmail password in case you had entered that. This can also be done by a a single copy paste action. Select the entire password in one go, don't worry about the spaces, and paste.
Return to the TB page with the Gmail settings, and paste (Ctrl+V) the password into the password field, replacing your own Gmail password in case you had entered that. Don't worry about spaces.
For accessing the database my personal preference is http://sqlitebrowser.org/
For editing templates I like to use http://brackets.io/