{"id":385,"date":"2025-05-30T14:42:33","date_gmt":"2025-05-30T13:42:33","guid":{"rendered":"https:\/\/exchangeforitpros.blog\/hotfix-update-may-2025\/"},"modified":"2025-06-14T15:14:02","modified_gmt":"2025-06-14T14:14:02","slug":"hotfix-update-may-2025","status":"publish","type":"post","link":"https:\/\/exchangeforitpros.blog\/en\/hotfix-update-may-2025\/","title":{"rendered":"Hotfix Update May 2025"},"content":{"rendered":"<div id=\"bsf_rt_marker\"><\/div>\t\t<div data-elementor-type=\"wp-post\" data-elementor-id=\"385\" class=\"elementor elementor-385 elementor-338\" data-elementor-post-type=\"post\">\n\t\t\t\t<div class=\"elementor-element elementor-element-7c8f8bce e-flex e-con-boxed e-con e-parent\" data-id=\"7c8f8bce\" data-element_type=\"container\" data-e-type=\"container\">\n\t\t\t\t\t<div class=\"e-con-inner\">\n\t\t<div class=\"elementor-element elementor-element-2f0f5dcf e-con-full e-flex e-con e-child\" data-id=\"2f0f5dcf\" data-element_type=\"container\" data-e-type=\"container\">\n\t\t\t\t<div class=\"elementor-element elementor-element-22a67bc0 elementor-widget elementor-widget-text-editor\" data-id=\"22a67bc0\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t\t\t\t\t\t<p>Just before the weekend, the Exchange Server team has released a hotfix update for the supported versions of Exchange Server 2019 (CU14 &amp; CU15) and Exchange Server 2016 (CU23).  <\/p><p>As the name suggests, this is not a security update that closes newly discovered security vulnerabilities. Rather, this hotfix update addresses some \u201ccode glitches\u201d of previous SUs and HUs.  <\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t<div class=\"elementor-element elementor-element-7361c145 e-con-full e-flex e-con e-child\" data-id=\"7361c145\" data-element_type=\"container\" data-e-type=\"container\">\n\t\t<div class=\"elementor-element elementor-element-1f0a27f2 e-con-full e-flex e-con e-child\" data-id=\"1f0a27f2\" data-element_type=\"container\" data-e-type=\"container\" data-settings=\"{&quot;background_background&quot;:&quot;classic&quot;}\">\n\t\t\t\t<div class=\"elementor-element elementor-element-22842bd6 elementor-widget elementor-widget-heading\" data-id=\"22842bd6\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t\t<h4 class=\"elementor-heading-title elementor-size-default\">Links<\/h4>\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-4f91d1a4 elementor-icon-list--layout-traditional elementor-list-item-link-full_width elementor-widget elementor-widget-icon-list\" data-id=\"4f91d1a4\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"icon-list.default\">\n\t\t\t\t\t\t\t<ul class=\"elementor-icon-list-items\">\n\t\t\t\t\t\t\t<li class=\"elementor-icon-list-item\">\n\t\t\t\t\t\t\t\t\t\t\t<a href=\"https:\/\/techcommunity.microsoft.com\/blog\/exchange\/released-may-2025-exchange-server-hotfix-updates\/4418786?WT.mc_id=M365-MVP-5003086\" target=\"_blank\">\n\n\t\t\t\t\t\t\t\t\t\t\t\t<span class=\"elementor-icon-list-icon\">\n\t\t\t\t\t\t\t<svg aria-hidden=\"true\" class=\"e-font-icon-svg e-fas-external-link-alt\" viewBox=\"0 0 512 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"><path d=\"M432,320H400a16,16,0,0,0-16,16V448H64V128H208a16,16,0,0,0,16-16V80a16,16,0,0,0-16-16H48A48,48,0,0,0,0,112V464a48,48,0,0,0,48,48H400a48,48,0,0,0,48-48V336A16,16,0,0,0,432,320ZM488,0h-128c-21.37,0-32.05,25.91-17,41l35.73,35.73L135,320.37a24,24,0,0,0,0,34L157.67,377a24,24,0,0,0,34,0L435.28,133.32,471,169c15,15,41,4.5,41-17V24A24,24,0,0,0,488,0Z\"><\/path><\/svg>\t\t\t\t\t\t<\/span>\n\t\t\t\t\t\t\t\t\t\t<span class=\"elementor-icon-list-text\">EHLO blog article<\/span>\n\t\t\t\t\t\t\t\t\t\t\t<\/a>\n\t\t\t\t\t\t\t\t\t<\/li>\n\t\t\t\t\t\t\t\t<li class=\"elementor-icon-list-item\">\n\t\t\t\t\t\t\t\t\t\t\t<a href=\"https:\/\/www.microsoft.com\/download\/details.aspx?id=108194&#038;WT.mc_id=M365-MVP-5003086\" target=\"_blank\">\n\n\t\t\t\t\t\t\t\t\t\t\t\t<span class=\"elementor-icon-list-icon\">\n\t\t\t\t\t\t\t<svg aria-hidden=\"true\" class=\"e-font-icon-svg e-fas-file-download\" viewBox=\"0 0 384 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"><path d=\"M224 136V0H24C10.7 0 0 10.7 0 24v464c0 13.3 10.7 24 24 24h336c13.3 0 24-10.7 24-24V160H248c-13.2 0-24-10.8-24-24zm76.45 211.36l-96.42 95.7c-6.65 6.61-17.39 6.61-24.04 0l-96.42-95.7C73.42 337.29 80.54 320 94.82 320H160v-80c0-8.84 7.16-16 16-16h32c8.84 0 16 7.16 16 16v80h65.18c14.28 0 21.4 17.29 11.27 27.36zM377 105L279.1 7c-4.5-4.5-10.6-7-17-7H256v128h128v-6.1c0-6.3-2.5-12.4-7-16.9z\"><\/path><\/svg>\t\t\t\t\t\t<\/span>\n\t\t\t\t\t\t\t\t\t\t<span class=\"elementor-icon-list-text\">Exchange 2019 CU15 - HU2<\/span>\n\t\t\t\t\t\t\t\t\t\t\t<\/a>\n\t\t\t\t\t\t\t\t\t<\/li>\n\t\t\t\t\t\t\t\t<li class=\"elementor-icon-list-item\">\n\t\t\t\t\t\t\t\t\t\t\t<a href=\"https:\/\/www.microsoft.com\/download\/details.aspx?id=108192&#038;WT.mc_id=M365-MVP-5003086\" target=\"_blank\">\n\n\t\t\t\t\t\t\t\t\t\t\t\t<span class=\"elementor-icon-list-icon\">\n\t\t\t\t\t\t\t<svg aria-hidden=\"true\" class=\"e-font-icon-svg e-fas-file-download\" viewBox=\"0 0 384 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"><path d=\"M224 136V0H24C10.7 0 0 10.7 0 24v464c0 13.3 10.7 24 24 24h336c13.3 0 24-10.7 24-24V160H248c-13.2 0-24-10.8-24-24zm76.45 211.36l-96.42 95.7c-6.65 6.61-17.39 6.61-24.04 0l-96.42-95.7C73.42 337.29 80.54 320 94.82 320H160v-80c0-8.84 7.16-16 16-16h32c8.84 0 16 7.16 16 16v80h65.18c14.28 0 21.4 17.29 11.27 27.36zM377 105L279.1 7c-4.5-4.5-10.6-7-17-7H256v128h128v-6.1c0-6.3-2.5-12.4-7-16.9z\"><\/path><\/svg>\t\t\t\t\t\t<\/span>\n\t\t\t\t\t\t\t\t\t\t<span class=\"elementor-icon-list-text\">Exchange 2019 CU14 - HU2<\/span>\n\t\t\t\t\t\t\t\t\t\t\t<\/a>\n\t\t\t\t\t\t\t\t\t<\/li>\n\t\t\t\t\t\t\t\t<li class=\"elementor-icon-list-item\">\n\t\t\t\t\t\t\t\t\t\t\t<a href=\"https:\/\/www.microsoft.com\/download\/details.aspx?id=108193&#038;WT.mc_id=M365-MVP-5003086\" target=\"_blank\">\n\n\t\t\t\t\t\t\t\t\t\t\t\t<span class=\"elementor-icon-list-icon\">\n\t\t\t\t\t\t\t<svg aria-hidden=\"true\" class=\"e-font-icon-svg e-fas-file-download\" viewBox=\"0 0 384 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"><path d=\"M224 136V0H24C10.7 0 0 10.7 0 24v464c0 13.3 10.7 24 24 24h336c13.3 0 24-10.7 24-24V160H248c-13.2 0-24-10.8-24-24zm76.45 211.36l-96.42 95.7c-6.65 6.61-17.39 6.61-24.04 0l-96.42-95.7C73.42 337.29 80.54 320 94.82 320H160v-80c0-8.84 7.16-16 16-16h32c8.84 0 16 7.16 16 16v80h65.18c14.28 0 21.4 17.29 11.27 27.36zM377 105L279.1 7c-4.5-4.5-10.6-7-17-7H256v128h128v-6.1c0-6.3-2.5-12.4-7-16.9z\"><\/path><\/svg>\t\t\t\t\t\t<\/span>\n\t\t\t\t\t\t\t\t\t\t<span class=\"elementor-icon-list-text\">Exchange 2016 CU23 - HU16<\/span>\n\t\t\t\t\t\t\t\t\t\t\t<\/a>\n\t\t\t\t\t\t\t\t\t<\/li>\n\t\t\t\t\t\t\t\t<li class=\"elementor-icon-list-item\">\n\t\t\t\t\t\t\t\t\t\t\t<a href=\"https:\/\/learn.microsoft.com\/exchange\/troubleshoot\/client-connectivity\/exchange-security-update-issues?WT.mc_id=M365-MVP-5003086\" target=\"_blank\">\n\n\t\t\t\t\t\t\t\t\t\t\t\t<span class=\"elementor-icon-list-icon\">\n\t\t\t\t\t\t\t<svg aria-hidden=\"true\" class=\"e-font-icon-svg e-fas-external-link-alt\" viewBox=\"0 0 512 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"><path d=\"M432,320H400a16,16,0,0,0-16,16V448H64V128H208a16,16,0,0,0,16-16V80a16,16,0,0,0-16-16H48A48,48,0,0,0,0,112V464a48,48,0,0,0,48,48H400a48,48,0,0,0,48-48V336A16,16,0,0,0,432,320ZM488,0h-128c-21.37,0-32.05,25.91-17,41l35.73,35.73L135,320.37a24,24,0,0,0,0,34L157.67,377a24,24,0,0,0,34,0L435.28,133.32,471,169c15,15,41,4.5,41-17V24A24,24,0,0,0,488,0Z\"><\/path><\/svg>\t\t\t\t\t\t<\/span>\n\t\t\t\t\t\t\t\t\t\t<span class=\"elementor-icon-list-text\">SU\/HU Installation FAQ<\/span>\n\t\t\t\t\t\t\t\t\t\t\t<\/a>\n\t\t\t\t\t\t\t\t\t<\/li>\n\t\t\t\t\t\t\t\t<li class=\"elementor-icon-list-item\">\n\t\t\t\t\t\t\t\t\t\t\t<a href=\"https:\/\/microsoft.github.io\/CSS-Exchange\/Setup\/SetupAssist\/?WT.mc_id=M365-MVP-5003086\" target=\"_blank\">\n\n\t\t\t\t\t\t\t\t\t\t\t\t<span class=\"elementor-icon-list-icon\">\n\t\t\t\t\t\t\t<svg aria-hidden=\"true\" class=\"e-font-icon-svg e-fas-external-link-alt\" viewBox=\"0 0 512 512\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\"><path d=\"M432,320H400a16,16,0,0,0-16,16V448H64V128H208a16,16,0,0,0,16-16V80a16,16,0,0,0-16-16H48A48,48,0,0,0,0,112V464a48,48,0,0,0,48,48H400a48,48,0,0,0,48-48V336A16,16,0,0,0,432,320ZM488,0h-128c-21.37,0-32.05,25.91-17,41l35.73,35.73L135,320.37a24,24,0,0,0,0,34L157.67,377a24,24,0,0,0,34,0L435.28,133.32,471,169c15,15,41,4.5,41-17V24A24,24,0,0,0,488,0Z\"><\/path><\/svg>\t\t\t\t\t\t<\/span>\n\t\t\t\t\t\t\t\t\t\t<span class=\"elementor-icon-list-text\">Setup Assist for HU installation errors<\/span>\n\t\t\t\t\t\t\t\t\t\t\t<\/a>\n\t\t\t\t\t\t\t\t\t<\/li>\n\t\t\t\t\t\t<\/ul>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t<div class=\"elementor-element elementor-element-6ed7f74d e-flex e-con-boxed e-con e-parent\" data-id=\"6ed7f74d\" data-element_type=\"container\" data-e-type=\"container\">\n\t\t\t\t\t<div class=\"e-con-inner\">\n\t\t<div class=\"elementor-element elementor-element-37c59fa e-con-full e-flex e-con e-child\" data-id=\"37c59fa\" data-element_type=\"container\" data-e-type=\"container\">\n\t\t\t\t<div class=\"elementor-element elementor-element-280bf39 elementor-widget elementor-widget-text-editor\" data-id=\"280bf39\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t\t\t\t\t\t<p>The upgrade scenario for installing the May hotfix update is similar to the last updates.<\/p><ul><li>If one of the three supported Exchange versions is already installed on your Exchange server, you can simply install the appropriate hotfix update.<\/li><li>If a cumulative update of a version is still installed, you must first update the affected systems to a supported cumulative update.<\/li><\/ul>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-0180a3d elementor-widget elementor-widget-image\" data-id=\"0180a3d\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"image.default\">\n\t\t\t\t\t\t\t\t\t\t\t\t<figure class=\"wp-caption\">\n\t\t\t\t\t\t\t\t\t\t<img fetchpriority=\"high\" decoding=\"async\" width=\"800\" height=\"207\" src=\"https:\/\/exchangeforitpros.blog\/wp-content\/uploads\/2025\/05\/May2025-HU-Path.webp\" class=\"attachment-large size-large wp-image-344\" alt=\"Flussdiagramm zum Update-Prozess von Exchange Server. Es zeigt zwei Pfade: Einer beginnt mit unterst\u00fctzten CUs (Exchange Server 2016 CU23, 2019 CU14 oder CU15) und f\u00fchrt direkt zur Installation der Mai 2023 Hotfixes. Der andere beginnt mit nicht unterst\u00fctzten CUs, f\u00fchrt zuerst zur Installation einer unterst\u00fctzten CU und danach zu den Hotfixes. Am Ende steht ein gr\u00fcnes Feld mit dem Hinweis, dass Exchange aktuell ist, sowie ein Link zum Health Checker. Ein zus\u00e4tzlicher Hinweis mit Warnsymbol verweist auf Hybrid-Konfigurationen und einen entsprechenden Microsoft-Link.\" srcset=\"https:\/\/exchangeforitpros.blog\/wp-content\/uploads\/2025\/05\/May2025-HU-Path.webp 999w, https:\/\/exchangeforitpros.blog\/wp-content\/uploads\/2025\/05\/May2025-HU-Path-300x78.webp 300w, https:\/\/exchangeforitpros.blog\/wp-content\/uploads\/2025\/05\/May2025-HU-Path-768x199.webp 768w\" sizes=\"(max-width: 800px) 100vw, 800px\" \/>\t\t\t\t\t\t\t\t\t\t\t<figcaption class=\"widget-image-caption wp-caption-text\">Source: Microsoft<\/figcaption>\n\t\t\t\t\t\t\t\t\t\t<\/figure>\n\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-41cb239 elementor-widget elementor-widget-spacer\" data-id=\"41cb239\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"spacer.default\">\n\t\t\t\t\t\t\t<div class=\"elementor-spacer\">\n\t\t\t<div class=\"elementor-spacer-inner\"><\/div>\n\t\t<\/div>\n\t\t\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-7dffd55 elementor-widget elementor-widget-heading\" data-id=\"7dffd55\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"heading.default\">\n\t\t\t\t\t<h2 class=\"elementor-heading-title elementor-size-default\">Dedicated hybrid application<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<div class=\"elementor-element elementor-element-d884286 elementor-widget elementor-widget-text-editor\" data-id=\"d884286\" data-element_type=\"widget\" data-e-type=\"widget\" data-widget_type=\"text-editor.default\">\n\t\t\t\t\t\t\t\t\t<p>October 2025 has a few tasks in store for Exchange admins. On October 14, not only Exchange Server 2016 &amp; 2019 reach their end of life, at least as far as the supported lifecycle is concerned, there is also extra work for hybrid Exchange environments.<\/p>\n<p>In October, the so-called Service Principal of the <strong>first-party application<\/strong> <em>Office 365 Exchange Online<\/em> will be switched off. After the lockdown, a local Exchange organization can no longer authenticate with this service principal. As a result, all functions of the full hybrid position (rich coexistence) will no longer work.&nbsp;<\/p>\n<p>For this to continue to work, a dedicated company application, the so-called <strong>Exchange Hybrid Application<\/strong>, must be created and configured in Entra. The steps are described in <a href=\"https:\/\/learn.microsoft.com\/exchange\/hybrid-deployment\/deploy-dedicated-hybrid-app?WT.mc_id=M365-MVP-5003086\" target=\"_blank\" rel=\"noopener\">this article<\/a>.<\/p>\n<p>We recommend setting this up before the switch-off date in October 2025, as this allows you to switch back to the old configuration at any time in order to carry out a fault analysis. After switching off the First-App Service Principal, commissioning is a bit like flying blind. Environments with a complex network infrastructure in particular present numerous hurdles that need to be overcome.<\/p><p>Incidentally, the company application itself is not deleted, as it is an integral part of conditional access filters.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t","protected":false},"excerpt":{"rendered":"<p>Just before the weekend, the Exchange Server team has released a hotfix update for the supported versions of Exchange Server 2019 (CU14 &amp; CU15) and Exchange Server 2016 (CU23). As the name suggests, this is not a security update that closes newly discovered security vulnerabilities. Rather, this hotfix update addresses some \u201ccode glitches\u201d of previous [&hellip;]<\/p>\n","protected":false},"author":3,"featured_media":333,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":false,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2}},"categories":[43],"tags":[44,45],"class_list":["post-385","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-exchange-server-en","tag-hotfix-en","tag-update-en"],"aioseo_notices":[],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"https:\/\/exchangeforitpros.blog\/wp-content\/uploads\/2025\/05\/Exchange_Server_Update_Header-01.webp","jetpack_likes_enabled":true,"jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/exchangeforitpros.blog\/en\/wp-json\/wp\/v2\/posts\/385","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/exchangeforitpros.blog\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/exchangeforitpros.blog\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/exchangeforitpros.blog\/en\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/exchangeforitpros.blog\/en\/wp-json\/wp\/v2\/comments?post=385"}],"version-history":[{"count":4,"href":"https:\/\/exchangeforitpros.blog\/en\/wp-json\/wp\/v2\/posts\/385\/revisions"}],"predecessor-version":[{"id":404,"href":"https:\/\/exchangeforitpros.blog\/en\/wp-json\/wp\/v2\/posts\/385\/revisions\/404"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/exchangeforitpros.blog\/en\/wp-json\/wp\/v2\/media\/333"}],"wp:attachment":[{"href":"https:\/\/exchangeforitpros.blog\/en\/wp-json\/wp\/v2\/media?parent=385"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/exchangeforitpros.blog\/en\/wp-json\/wp\/v2\/categories?post=385"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/exchangeforitpros.blog\/en\/wp-json\/wp\/v2\/tags?post=385"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}