I can not access gmail. How can I revert to my earlier eM Client version?


EM Client was forced to use Google OAuth 2.0. Even if you did revert to an earlier version you would only have a working em client application for today. Google will no longer accept the OpenID 2.0 after today. 

you want to download the “6.0.21372.0” version 

Hello Bob, exactly as Josh suggested above, it is no longer possible to use older releases of eM Client with your Gmail account as Google has shutdown the support for regular web access password authentication, please make sure to keep your application up to date.

Using the latest release eM Client should allow you to authenticate with your Gmail account through a web browser window that will request your password and access to your server items, please make sure to confirm this to start using your account in eM Client again, more info about the feature here: http://www.emclient.com/blog/em-client-now-features-oauth-authentication-with-gmail-124

Hope this helps.

But to my knowledge build “6.0.21372.0” uses IMAP and not OpenID as its default connection to gmail. OAuth 2.0 replaced OpenID 2.0 and NOT IMAP/SMTP validation. Other email clients use IMAP/SMTP only validation. 

IMAP is the protocol used for synchronizing the data with the server, OAuth serves for authentication and storing of the account password that is now being fetched from the server as a token, that eM Client stores for communication with the server.

Google no longer supports authenticating with the server using standard password authentication, since it’s been almost a year since they have labeled the process as “less secure” and started supporting OAuth instead.