G Suite notice about SMS Backup+ becoming restricted

[Note added by @kurahaupo, 2020-07-08]

1. This thread does have useful information but it is somewhat buried because the thread is so long. Please read through it before adding more comments. If you’re just looking for a quick fix, there’s an explanation at the top of #972.
2. Although this report dates from June 2019, in July 2020 G-suite users are being notified (again) that new installations of SMS Backup+ won’t get Gmail sensitive scope access; it’s the same problem, just different timing.
3. This policy change should not affect access to Calendars. If you have a problem with calendars, raise a separate ticket. (Note: do not enable Connect your Gmail account (unsupported), as that’s only for Gmail, not for Calendars.)
4. The changes to sensitive scope access are explained at https://developers.google.com/terms/api-services-user-data-policy#additional-requirements-for-specific-api-scopes A major use-case is being able to read SMS & MMS alongside email & hangouts messages, and that ought to be sufficient justification under term 3 of the rules “Applications that enhance the email experience for productivity purposes”, but it’s hard to argue that case when the name says “Backup”.

[Original report follows]

I received the attached email from Google that your app will become restricted on 7/8. Thought you’d like to know. SMS Backup.pdf

[jberkel]

Hello everyone. I’m sorry about this situation, SMS Backup+ will no longer have access to Gmail, mainly because it’s not an email reading app.

I applied for an exception but it was declined, as expected. Vanilla IMAP might work, but for how long I wonder. And it’s very tricky to set up for a casual user. Unfortunately the Android platform is getting more and more closed.

I’m not sure what to do at this point, either remove the app from the store or release a new version which removes the automatic account setup, since that is broken / will be broken soon.

[chwaze]

I have confirmed that @Jasonfhaught 's IMAP setup works; however, I used an app password instead of entering my own password because I have 2-Step-Verification turned on in my Gmail account. I think this is a more secure method to use on all counts.

To review (and format the steps for better readability here), these are the changes you need to make in your Gmail account and the SMS Backup+ app:

Gmail Account Setup

The following steps assume you are accessing the Gmail account from a desktop browser.

1. Click the Settings cog icon in the top right corner
2. Click “Settings” in the dropdown menu
3. Click the “Forwarding and POP/IMAP” tab below the Settings heading
4. Select “Enable IMAP” for Status in the IMAP access section
5. Click the “Save Changes” button at the bottom of the tab
6. Click your account avatar in the top right corner
7. Click the “Google Account” button
8. Click “Security” in the left navigation
9. Under “Signing in to Google”, click “App passwords”
10. Re-enter your Gmail password
11. Click the dropdown menu titled “Select app” and choose “Other (Custom name)”
12. Enter a name for SMS Backup+ (e.g., “sms-backup-plus”)
13. Click the “Generate” button.
14. Make note of the 16-character password and click the “DONE” link

SMS Backup+ Setup

1. Press “Advanced settings”
2. Press “Custom IMAP server”
3. Press “Authentication” and select “Plain text”
4. For server address and port, enter imap.gmail.com:993
5. For IMAP account/e-mail address, enter your Gmail e-mail address
6. For IMAP account password, enter the app password created in step 14 of Gmail Account Setup
7. For Security, confirm it is set to TLS