Users with older versions of Outlook, which is any version from Outlook 2019 and older, may be affected if they have an MSI or LTSC version that does not receive updates.  If your Outlook 2016 or newer recieves updates (should be 170000.***** or higher if fully updated). You will no longer be able to set up a POP or IMAP account in classic Outlook to connect to Outlook.com; you will need to add it using File > Add Account and let auto account set up add the account as a Microsoft Exchange account.

Classic Outlook desktop versions older than 11601.10000 do not support Modern Authentication for Outlook.com. Users will need to use Outlook on the web, new Outlook, or a third-party mail client, such as  eM Client and Thunderbird. Both support modern authentication using POP or IMAP.

From Microsoft: The following versions of Outlook Desktop do not support Modern Authentication for Outlook.com:  Outlook 2007, Outlook 2010, Outlook 2013, Outlook 2016 MSI, Outlook 2019 LTSC. Any release of Outlook Desktop with a version less than 11601.10000 does not support Modern Authentication for Outlook.com.

Note: if you are using a third party mail app, either on desktop or mobile device, and Outlook.com stops syncing, first remove the account and add it back. If the client supports modern auth, it will add the account back using modern auth. If you are using Thunderbird or eM client, you can update the account authentication without removing the account.

By the end of June 2024, users still using basic auth to connect to Outlook.com accounts will receive an email notifying them one or more devices is using basic authentication. On September 16th, 2024, users will be unable to use Basic Authentication to access any Outlook account.

Those most affected by this change will be users of classic Outlook 2007 to 2019. It is recommended to use Microsoft Exchange services to sync classic Outlook and Outlook.com, not POP or IMAP (which will no longer work to connect Outlook.com to Outlook.)

Any app that brings up the Microsoft login dialog you see when you sign in using a browser will work after September 16. That screen means it uses modern auth (also known as oAuth2.) If you have a normal password dialog when you sign in, the app does not support modern auth.

If you have 2-step verification enabled and are using an app password, that app is using basic auth. App passwords will be disabled / removed when basic auth is turned off.

Microsoft has stated that users signing into Outlook.com using apps that use basic auth may have repeated password prompts in their email apps. Consider it a warning that the app is using basic auth. After September 16th, these apps will not connect to Outlook.com.

User Questions

Q: Is my Gmail or other non-Microsoft account affected by this change?

A: No. Only Outlook.com accounts, including Hotmail, live.com and MSN addresses. Users with custom domains from one of the defunct custom domain programs are also affected.

If you have the account added to Outlook as a Microsoft Exchange account and are using a version of Outlook currently in support, you are all set.

If the account is added to any version of Outlook Classic as a POP or IMAP account, it will stop working in September. If you have a supported version of Outlook, you’ll either need to remove the account and add it back using auto account setup so it’s added as an Exchange account, or you will need to use another mail app. Both eM Client and Thunderbird support modern authentication using POP or IMAP.

If you are not using a supported version of Outlook Classic – this includes Outlook 2013 and all older versions, volume license, some single purchase retail licenses – you need a new mail app, either a modern version of Outlook or a different client.

If you are using Windows Live Mail, it’s past time to ditch it. eM client is a good replacement and can import your mail from WLM.

Other older email clients, such as Apple mail on older macOS or iOS are not supported. If you get repeated password prompts, it is using basic auth. If you have a newer iPhone or iPad, it supports modern auth but if the account was added to the app years ago, you'll need to remove the account and add it back. Apple will not automatically switch the account to use modern auth.

Q: I have my Gmail account configured to download my Outlook.com mail. Will this affect me?

A: If you have the outlook.com account added to Gmail as a POP account, it will quit working. If you added it as a gmailify account, it will continue to work as gmailify uses modern auth. However, you can only use gmailify with one account.