{"id":835,"date":"2026-09-22T10:04:51","date_gmt":"2026-09-22T10:04:51","guid":{"rendered":"https:\/\/syncpenguin.com\/blog\/?p=835"},"modified":"2026-09-23T05:40:07","modified_gmt":"2026-09-23T05:40:07","slug":"how-to-keep-ews-working-in-exchange-online-after-october-2026","status":"publish","type":"post","link":"https:\/\/syncpenguin.com\/blog\/how-to-keep-ews-working-in-exchange-online-after-october-2026\/","title":{"rendered":"How to keep EWS working in Exchange Online after October 2026"},"content":{"rendered":"\n<p>Microsoft is retiring Exchange Web Services (EWS) in Exchange Online (Microsoft 365 cloud), and the first deadline is days away. If your organization relies on an app that syncs mail, calendars, tasks, or contacts over EWS, you can keep it running until the final shutdown with a short PowerShell change. Here&#8217;s what&#8217;s happening and how to do it.<\/p>\n\n\n\n<h4>The timeline<\/h4>\n\n\n\n<p>A phased EWS disablement begins October 1st, 2026, with permanent shutdown starting April 1st, 2027.<\/p>\n\n\n\n<p>Beginning October 1st, EWS will be blocked unless the tenant configures an <code>AppID <\/code>allow list and sets <code>EWSEnabled<\/code> to <code>True<\/code>. Without admin action, Microsoft will set <code>EWSEnabled <\/code>to <code>False <\/code>and EWS apps will stop working. After April 1st, 2027, EWS access will be permanently removed with no re-enablement. This only affects cloud Microsoft 365, no changes are being made to EWS in Exchange Server (on-premises).<\/p>\n\n\n\n<h4>1. Find the app IDs you need to allow<\/h4>\n\n\n\n<p>The new allow list works on Entra application IDs. Unlike the older <code>EwsAllowList<\/code>, which filters on an easily spoofed user agent string, <code>EWSAllowedAppIDs <\/code>relies on the special application identifier registered in Microsoft Entra ID. Collect the Application (client) ID for every EWS app your organization still uses. <strong>For SyncPenguin, use<\/strong>:<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>98874266-492b-43c2-9259-6a1e9618c17c\r\naf15e02e-df4e-4ea2-b8ae-19a9b7542a50\r\nc3eebf7d-e7a6-4569-af78-f270f3221cc3<\/code><\/pre>\n\n\n\n<h4>2. Enable EWS and add the app to the allow list<\/h4>\n\n\n\n<p>Connect to Exchange Online PowerShell (as an admin) and run the following script:<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>Connect-ExchangeOnline\n\n$appIds = @(\r\n    \"98874266-492b-43c2-9259-6a1e9618c17c\",\r\n    \"af15e02e-df4e-4ea2-b8ae-19a9b7542a50\",\r\n    \"c3eebf7d-e7a6-4569-af78-f270f3221cc3\"\r\n) # SyncPenguin app IDs. Change or add any others to the list\n\n$current = (Get-OrganizationConfig -RetrieveEwsOperationAccessPolicy).EwsAllowedAppIDs\n$updated = @(\n    $current -split \",\" | ForEach-Object { $_.Trim() } | Where-Object { $_ }\n    $appIds\n) | Select-Object -Unique\n\nSet-OrganizationConfig -EwsEnabled $true -EwsAllowedAppIDs ($updated -join \",\")<\/code><\/pre>\n\n\n\n<p>Note that when <code>EwsEnabled <\/code>is <code>True<\/code>, only applications specified in the allow list can access EWS, so include everything you still depend on.<\/p>\n\n\n\n<h4>3. Verify<\/h4>\n\n\n\n<pre class=\"wp-block-code\"><code>Get-OrganizationConfig -RetrieveEwsOperationAccessPolicy | Format-List EwsEnabled, EwsAllowedAppIDs<\/code><\/pre>\n\n\n\n<p>Note that the configuration change can take up to 24 hours to propagate. Also, be sure to check that the mailboxes being synced haven&#8217;t been individually blocked, because Exchange Online will only allow a mailbox to use EWS if both the organization and mailbox settings are true.<\/p>\n\n\n\n<h4>Alternative solution without allow list<\/h4>\n\n\n\n<p>MIcrosoft will automatically change the value of <code>EwsEnabled<\/code>  from <code>Null <\/code>to <code>False <\/code>starting October, 2026. You can then just re-enable EWS by setting <code>EWSEnabled<\/code> to back <code>Null<\/code> <strong>after it was automatically set to <code>False<\/code> by Microsoft (after October 1st)<\/strong>. There will be a brief service interruption while the change takes effect, but re-enablement remains available until April 1st, 2027.<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>Set-OrganizationConfig -EWSEnabled $null<\/code><\/pre>\n\n\n\n<h4>What SyncPenguin customers should do<\/h4>\n\n\n\n<p>We recommend reconnecting your SyncPenguin accounts to switch them from EWS to the Microsoft Graph API, as described in <a href=\"https:\/\/syncpenguin.com\/blog\/syncpenguin-is-moving-from-ews-to-microsoft-graph-api-what-you-need-to-know-in-2026\/\">this blog post<\/a>. If you&#8217;re not ready yet, you can extend EWS access using the steps above, but keep in mind this only works until April 1st, 2027. Feel free to <a href=\"https:\/\/syncpenguin.com\/contact-us\">contact us<\/a> if you need any help during the transition period.<\/p>\n\n\n\n<p>For official information about Microsoft EWS deprecation, please <a href=\"https:\/\/techcommunity.microsoft.com\/blog\/exchange\/exchange-online-ews-your-time-is-almost-up\/4492361\">check this article<\/a>.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Microsoft is retiring Exchange Web Services (EWS) in Exchange Online (Microsoft 365 cloud), and the first deadline is days away. If your organization relies on an app that syncs mail, calendars, tasks, or contacts over EWS, you can keep it running until the final shutdown with a short PowerShell change. Here&#8217;s what&#8217;s happening and how&#8230;<\/p>\n","protected":false},"author":3,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_kad_post_transparent":"","_kad_post_title":"","_kad_post_layout":"","_kad_post_sidebar_id":"","_kad_post_content_style":"","_kad_post_vertical_padding":"","_kad_post_feature":"","_kad_post_feature_position":"","_kad_post_header":false,"_kad_post_footer":false},"categories":[45,30,16],"tags":[51,46,50],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v19.8 - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>How to keep EWS working in Exchange Online after October 2026 | SyncPenguin Blog | Two-way and one-way automatic sync of calendar meetings, contacts, and tasks<\/title>\n<meta name=\"description\" content=\"Learn how to keep EWS working after October 2026 deprecation deadline and until April 2027 via EwsEnabled parameter.\" \/>\n<meta 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