Т.е. авторизация на google imap по простому user/pass перестанет работать. только клиенты с поддержкой oauth2.
On May 30, you may lose access to apps that are using less secure sign-in technology
To help keep your account secure, Google will no longer support the use of third-party apps or devices which ask you to sign in to your Google Account using only your username and password. Instead, you’ll need to sign in using Sign in with Google or other more secure technologies, like OAuth 2.0. Learn more