diff --git a/admin/tool/componentlibrary/content/bootstrap/utilities/borders.md b/admin/tool/componentlibrary/content/bootstrap/utilities/borders.md
index c29d73d6a26..d6acd8194b3 100644
--- a/admin/tool/componentlibrary/content/bootstrap/utilities/borders.md
+++ b/admin/tool/componentlibrary/content/bootstrap/utilities/borders.md
@@ -16,9 +16,9 @@ Use border utilities to add or remove an element's borders. Choose from all bord
 {{< example class="bd-example-border-utils">}}
 <span class="border"></span>
 <span class="border-top"></span>
-<span class="border-right"></span>
+<span class="border-end"></span>
 <span class="border-bottom"></span>
-<span class="border-left"></span>
+<span class="border-start"></span>
 {{< /example >}}
 
 ### Subtractive
@@ -26,9 +26,9 @@ Use border utilities to add or remove an element's borders. Choose from all bord
 {{< example class="bd-example-border-utils bd-example-border-utils-0" >}}
 <span class="border-0"></span>
 <span class="border-top-0"></span>
-<span class="border-right-0"></span>
+<span class="border-end-0"></span>
 <span class="border-bottom-0"></span>
-<span class="border-left-0"></span>
+<span class="border-start-0"></span>
 {{< /example >}}
 
 ## Border color
@@ -51,9 +51,9 @@ Add classes to an element to easily round its corners.
 {{< example>}}
 {{< placeholder width="75" height="75" class="rounded" title="Example rounded image" >}}
 {{< placeholder width="75" height="75" class="rounded-top" title="Example top rounded image" >}}
-{{< placeholder width="75" height="75" class="rounded-right" title="Example right rounded image" >}}
+{{< placeholder width="75" height="75" class="rounded-end" title="Example right rounded image" >}}
 {{< placeholder width="75" height="75" class="rounded-bottom" title="Example bottom rounded image" >}}
-{{< placeholder width="75" height="75" class="rounded-left" title="Example left rounded image" >}}
+{{< placeholder width="75" height="75" class="rounded-start" title="Example left rounded image" >}}
 {{< placeholder width="75" height="75" class="rounded-circle" title="Completely round image" >}}
 {{< placeholder width="150" height="75" class="rounded-pill" title="Rounded pill image" >}}
 {{< placeholder width="75" height="75" class="rounded-0" title="Example non-rounded image (overrides rounding applied elsewhere)" >}}
diff --git a/admin/tool/componentlibrary/hugo/site/layouts/shortcodes/mustache.html b/admin/tool/componentlibrary/hugo/site/layouts/shortcodes/mustache.html
index 0246c58e876..4d5413cb785 100644
--- a/admin/tool/componentlibrary/hugo/site/layouts/shortcodes/mustache.html
+++ b/admin/tool/componentlibrary/hugo/site/layouts/shortcodes/mustache.html
@@ -36,7 +36,7 @@
             </a>
         </div>
     </nav>
-    <div class="tab-content border-left border-bottom border-right p-3 bg-white" id="nav-tabContent">
+    <div class="tab-content border-start border-bottom border-end p-3 bg-white" id="nav-tabContent">
         <div class="tab-pane fade show active" id="nav-rendered{{- .Position.LineNumber -}}" role="tabpanel" aria-labelledby="nav-rendered{{- .Position.LineNumber -}}-tab">
             <div data-region="mustacherendered" class="{{ with .Get "class" }}{{ . }}{{ end }}">
                 <div class="d-flex justify-content-center my-5">
diff --git a/admin/tool/moodlenet/templates/select_page.mustache b/admin/tool/moodlenet/templates/select_page.mustache
index a49903bd244..9075ea5311d 100644
--- a/admin/tool/moodlenet/templates/select_page.mustache
+++ b/admin/tool/moodlenet/templates/select_page.mustache
@@ -37,12 +37,12 @@
         <input type="text"
                data-region="search-input"
                id="searchinput"
-               class="form-control form-control-lg searchinput border-right-0 px-3 py-2"
+               class="form-control form-control-lg searchinput border-end-0 px-3 py-2"
                placeholder="{{#str}} search, core {{/str}}"
                name="search"
                autocomplete="off"
         >
-        <div class="searchbar-append d-flex border border-secondary border-left-0 px-3 py-2">
+        <div class="searchbar-append d-flex border border-secondary border-start-0 px-3 py-2">
             <div data-region="search-icon">
                 {{#pix}} a/search, core {{/pix}}
             </div>
diff --git a/blocks/myoverview/templates/placeholder-course-list-item.mustache b/blocks/myoverview/templates/placeholder-course-list-item.mustache
index 409955e9106..af150cdf168 100644
--- a/blocks/myoverview/templates/placeholder-course-list-item.mustache
+++ b/blocks/myoverview/templates/placeholder-course-list-item.mustache
@@ -22,7 +22,7 @@
     Example context (json):
     {}
 }}
-<li class="list-group-item course-listitem border-left-0 border-right-0 border-top-0 px-2 rounded-0">
+<li class="list-group-item course-listitem border-start-0 border-end-0 border-top-0 px-2 rounded-0">
     <div class="row">
         <div class="col-md-2 d-flex align-items-center">
             <div class="bg-pulse-grey card-img w-100" style="height: 1rem; width: 1rem;"></div>
diff --git a/blocks/myoverview/templates/view-list.mustache b/blocks/myoverview/templates/view-list.mustache
index fb224891799..9602e8619ef 100644
--- a/blocks/myoverview/templates/view-list.mustache
+++ b/blocks/myoverview/templates/view-list.mustache
@@ -38,7 +38,7 @@
 
 <ul class="list-group">
     {{#courses}}
-        <li class="list-group-item course-listitem border-left-0 border-right-0 border-top-0 px-2 rounded-0"
+        <li class="list-group-item course-listitem border-start-0 border-end-0 border-top-0 px-2 rounded-0"
             data-region="course-content"
             data-course-id="{{{id}}}">
             <div class="row">
diff --git a/blocks/myoverview/templates/view-summary.mustache b/blocks/myoverview/templates/view-summary.mustache
index 6e84d05c130..11a87bb4803 100644
--- a/blocks/myoverview/templates/view-summary.mustache
+++ b/blocks/myoverview/templates/view-summary.mustache
@@ -38,7 +38,7 @@
 }}
 <div role="list">
 {{#courses}}
-    <div class="course-summaryitem list-group-item course-listitem border-left-0 border-right-0 border-top-0 px-2 rounded-0" role="listitem"
+    <div class="course-summaryitem list-group-item course-listitem border-start-0 border-end-0 border-top-0 px-2 rounded-0" role="listitem"
         data-region="course-content"
         data-course-id="{{{id}}}">
         <div class="row">
diff --git a/course/templates/activity_list.mustache b/course/templates/activity_list.mustache
index 33e30bd44b4..23159221d89 100644
--- a/course/templates/activity_list.mustache
+++ b/course/templates/activity_list.mustache
@@ -27,11 +27,11 @@
             <label for="search">
                 <span class="sr-only">{{#str}} searchactivitiesbyname, course {{/str}}</span>
             </label>
-            <input type="text" name="search" id="search" class="form-control rounded-left" autocomplete="off"
+            <input type="text" name="search" id="search" class="form-control rounded-start" autocomplete="off"
                    placeholder="{{#str}}search, core {{/str}}" {{#query}} value="{{query}}" autofocus {{/query}}
             >
             <div class="input-group-append">
-                <button type="submit" class="btn btn-outline-secondary rounded-right">
+                <button type="submit" class="btn btn-outline-secondary rounded-end">
                     <i class="icon fa fa-search fa-fw m-0" aria-hidden="true"></i>
                     <span class="sr-only">{{#str}}submitsearch, course {{/str}}</span>
                 </button>
diff --git a/course/templates/activitychooser.mustache b/course/templates/activitychooser.mustache
index 67b2cfb952d..3a50df1b58b 100644
--- a/course/templates/activitychooser.mustache
+++ b/course/templates/activitychooser.mustache
@@ -135,7 +135,7 @@
                         </a>
                         {{/recommendedBeginning}}
                     </div>
-                    <div class="tab-content flex-fill border-left border-right border-bottom bg-light" id="tabbed-activities-{{uniqid}}">
+                    <div class="tab-content flex-fill border-start border-end border-bottom bg-light" id="tabbed-activities-{{uniqid}}">
                         <div class="tab-pane {{#favouritesFirst}}active{{/favouritesFirst}}" id="starred-{{uniqid}}" data-region="favourites" role="tabpanel" aria-labelledby="starred-tab-{{uniqid}}">
                             <div class="optionscontainer d-flex flex-wrap p-1 mw-100 position-relative" role="menubar" data-region="chooser-options-container" data-render="favourites-area">
                                 {{>core_course/local/activitychooser/favourites}}
diff --git a/lib/templates/editswitch.mustache b/lib/templates/editswitch.mustache
index 19b028acd1d..1e1ebf9e640 100644
--- a/lib/templates/editswitch.mustache
+++ b/lib/templates/editswitch.mustache
@@ -31,7 +31,7 @@
         "legacyseturl": "/editmode.php"
     }
 }}
-<div class="divider border-left h-75 align-self-center ms-1 me-3"></div>
+<div class="divider border-start h-75 align-self-center ms-1 me-3"></div>
 <form action="{{{legacyseturl}}}" method="post" class="d-flex align-items-center editmode-switch-form">
     <div class="input-group">
         <label class="me-2 mb-0 {{#checked}}text-primary{{/checked}}" for="{{uniqid}}-editingswitch">
diff --git a/lib/templates/emoji/picker.mustache b/lib/templates/emoji/picker.mustache
index 83cb1b6b4f0..b2da1a7cd4c 100644
--- a/lib/templates/emoji/picker.mustache
+++ b/lib/templates/emoji/picker.mustache
@@ -128,7 +128,7 @@
             </div>
             <input
                 type="text"
-                class="form-control border-left-0"
+                class="form-control border-start-0"
                 placeholder="{{#str}} search, core {{/str}}"
                 aria-label="{{#str}} search, core {{/str}}"
                 data-region="search-input"
diff --git a/lib/templates/loginform.mustache b/lib/templates/loginform.mustache
index f12948067cc..55a8a25e93c 100644
--- a/lib/templates/loginform.mustache
+++ b/lib/templates/loginform.mustache
@@ -208,7 +208,7 @@
             <div class="login-languagemenu">
                 {{>core/action_menu}}
             </div>
-            <div class="divider border-left align-self-center mx-3"></div>
+            <div class="divider border-start align-self-center mx-3"></div>
         {{/languagemenu}}
         <button type="button" class="btn btn-secondary" {{!
         }} data-modal="alert"{{!
diff --git a/lib/templates/user_menu.mustache b/lib/templates/user_menu.mustache
index c129661eaad..6ae3da47c03 100644
--- a/lib/templates/user_menu.mustache
+++ b/lib/templates/user_menu.mustache
@@ -57,7 +57,7 @@
         <span class="login ps-2">
             {{#guest}}
                 {{#str}} loggedinasguest, core {{/str}}
-                <div class="divider border-left h-75 align-self-center mx-2"></div>
+                <div class="divider border-start h-75 align-self-center mx-2"></div>
             {{/guest}}
             {{#url}}
                 <a href="{{url}}">{{#str}} login, core {{/str}}</a>
diff --git a/message/templates/message_index.mustache b/message/templates/message_index.mustache
index 361ca6b250d..fa853fe5d93 100644
--- a/message/templates/message_index.mustache
+++ b/message/templates/message_index.mustache
@@ -44,7 +44,7 @@
     <div class="container-fluid">
         <div class="row h-100 g-0">
             <div class="col-4 d-flex flex-column conversationcontainer">
-                <div class="border-right h-100">
+                <div class="border-end h-100">
                     <div class="panel-header-container" data-region="panel-header-container">
                         {{> core_message/message_drawer_view_overview_header }}
                         {{> core_message/message_drawer_view_search_header }}
diff --git a/mod/data/templates/action_bar.mustache b/mod/data/templates/action_bar.mustache
index 355f4121a0c..31482366279 100644
--- a/mod/data/templates/action_bar.mustache
+++ b/mod/data/templates/action_bar.mustache
@@ -84,7 +84,7 @@
     <div class="row">
         <div class="d-flex">
             {{#hasback}}
-                <div class="navitem mb-0 backbutton border-right">
+                <div class="navitem mb-0 backbutton border-end">
                     <a href="{{backurl}}" role="button" title="{{backtitle}}" class="d-flex align-items-center">{{!
                     }}{{#pix}} i/previous, moodle {{/pix}}{{!
                     }}</a>
diff --git a/mod/data/templates/fields_action_bar.mustache b/mod/data/templates/fields_action_bar.mustache
index cd90004aeca..2eaf61489d1 100644
--- a/mod/data/templates/fields_action_bar.mustache
+++ b/mod/data/templates/fields_action_bar.mustache
@@ -53,7 +53,7 @@
     <div class="row">
         <div class="d-flex">
             {{#hasback}}
-                <div class="navitem mb-0 backbutton border-right">
+                <div class="navitem mb-0 backbutton border-end">
                     <a href="{{backurl}}" role="button" title="{{backtitle}}" class="d-flex align-items-center">{{!
                     }}{{#pix}} i/previous, moodle {{/pix}}{{!
                     }}</a>
diff --git a/mod/data/templates/presets.mustache b/mod/data/templates/presets.mustache
index ddcd688402f..ebf1fbdeeaa 100644
--- a/mod/data/templates/presets.mustache
+++ b/mod/data/templates/presets.mustache
@@ -77,7 +77,7 @@
             <tbody>
             {{#presets}}
                 <tr>
-                    <td class="p-4 border-right">
+                    <td class="p-4 border-end">
                         <input type="radio" name="fullname" value="{{userid}}/{{shortname}}" data-cmid="{{cmid}}" aria-labelledby="preset-name-{{presetindex}}" >
                     </td>
                     <td class="p-4">
diff --git a/reportbuilder/classes/table/custom_report_table.php b/reportbuilder/classes/table/custom_report_table.php
index c4a2ac582c1..947e8751301 100644
--- a/reportbuilder/classes/table/custom_report_table.php
+++ b/reportbuilder/classes/table/custom_report_table.php
@@ -263,7 +263,7 @@ class custom_report_table extends base_report_table {
             ]);
 
             echo html_writer::tag('th', $headercell, [
-                'class' => 'border-right border-left',
+                'class' => 'border-end border-start',
                 'scope' => 'col',
                 'data-region' => 'column-header',
                 'data-column-id' => $column->get_persistent()->get('id'),
diff --git a/reportbuilder/templates/local/sidebar-menu/area.mustache b/reportbuilder/templates/local/sidebar-menu/area.mustache
index c377ac3ff2f..08cdcee8514 100644
--- a/reportbuilder/templates/local/sidebar-menu/area.mustache
+++ b/reportbuilder/templates/local/sidebar-menu/area.mustache
@@ -39,7 +39,7 @@
         </label>
         <input id="reportbuilder-sidebar-search"
                type="text"
-               class="form-control rounded-left border-right-0"
+               class="form-control rounded-start border-end-0"
                placeholder="{{#str}} search, core_search {{/str}}"
                aria-label="{{#str}} search, core_search {{/str}}"
                data-action="sidebar-search">
diff --git a/theme/boost/scss/moodle/bs5-bridge.scss b/theme/boost/scss/moodle/bs5-bridge.scss
index 817f56494c0..7a1e2466fa3 100644
--- a/theme/boost/scss/moodle/bs5-bridge.scss
+++ b/theme/boost/scss/moodle/bs5-bridge.scss
@@ -61,3 +61,22 @@
         @extend .text#{$infix}-right;
     }
 }
+
+.border-start {
+    @extend .border-left;
+}
+.border-end {
+    @extend .border-right;
+}
+.border-start-0 {
+    @extend .border-left-0;
+}
+.border-end-0 {
+    @extend .border-right-0;
+}
+.rounded-start {
+    @extend .rounded-left;
+}
+.rounded-end {
+    @extend .rounded-right;
+}
diff --git a/theme/boost/style/moodle.css b/theme/boost/style/moodle.css
index c92990f02da..55ebc57938b 100644
--- a/theme/boost/style/moodle.css
+++ b/theme/boost/style/moodle.css
@@ -19421,7 +19421,7 @@ button.bg-dark:focus {
   border-top: 1px solid #dee2e6 !important;
 }
 
-.border-right {
+.border-right, .border-end {
   border-right: 1px solid #dee2e6 !important;
 }
 
@@ -19429,7 +19429,7 @@ button.bg-dark:focus {
   border-bottom: 1px solid #dee2e6 !important;
 }
 
-.border-left {
+.border-left, .border-start {
   border-left: 1px solid #dee2e6 !important;
 }
 
@@ -19441,7 +19441,7 @@ button.bg-dark:focus {
   border-top: 0 !important;
 }
 
-.border-right-0 {
+.border-right-0, .border-end-0 {
   border-right: 0 !important;
 }
 
@@ -19449,7 +19449,7 @@ button.bg-dark:focus {
   border-bottom: 0 !important;
 }
 
-.border-left-0 {
+.border-left-0, .border-start-0 {
   border-left: 0 !important;
 }
 
@@ -19502,7 +19502,7 @@ button.bg-dark:focus {
   border-top-right-radius: 0.5rem !important;
 }
 
-.rounded-right {
+.rounded-right, .rounded-end {
   border-top-right-radius: 0.5rem !important;
   border-bottom-right-radius: 0.5rem !important;
 }
@@ -19512,7 +19512,7 @@ button.bg-dark:focus {
   border-bottom-left-radius: 0.5rem !important;
 }
 
-.rounded-left {
+.rounded-left, .rounded-start {
   border-top-left-radius: 0.5rem !important;
   border-bottom-left-radius: 0.5rem !important;
 }
diff --git a/theme/boost/templates/navbar.mustache b/theme/boost/templates/navbar.mustache
index ff274fd6cf8..653627166d7 100644
--- a/theme/boost/templates/navbar.mustache
+++ b/theme/boost/templates/navbar.mustache
@@ -85,11 +85,11 @@
         <div id="usernavigation" class="navbar-nav ms-auto">
             {{# output.search_box }}
                 {{{ output.search_box }}}
-                <div class="divider border-left h-75 align-self-center mx-1"></div>
+                <div class="divider border-start h-75 align-self-center mx-1"></div>
             {{/output.search_box}}
             {{#langmenu}}
                 {{> theme_boost/language_menu }}
-                <div class="divider border-left h-75 align-self-center mx-1"></div>
+                <div class="divider border-start h-75 align-self-center mx-1"></div>
             {{/langmenu}}
             {{{ output.navbar_plugin_output }}}
             <div class="d-flex align-items-stretch usermenu-container" data-region="usermenu">
diff --git a/theme/classic/style/moodle.css b/theme/classic/style/moodle.css
index b0c5dafacc4..9fa2cae4ee3 100644
--- a/theme/classic/style/moodle.css
+++ b/theme/classic/style/moodle.css
@@ -19421,7 +19421,7 @@ button.bg-dark:focus {
   border-top: 1px solid #dee2e6 !important;
 }
 
-.border-right {
+.border-right, .border-end {
   border-right: 1px solid #dee2e6 !important;
 }
 
@@ -19429,7 +19429,7 @@ button.bg-dark:focus {
   border-bottom: 1px solid #dee2e6 !important;
 }
 
-.border-left {
+.border-left, .border-start {
   border-left: 1px solid #dee2e6 !important;
 }
 
@@ -19441,7 +19441,7 @@ button.bg-dark:focus {
   border-top: 0 !important;
 }
 
-.border-right-0 {
+.border-right-0, .border-end-0 {
   border-right: 0 !important;
 }
 
@@ -19449,7 +19449,7 @@ button.bg-dark:focus {
   border-bottom: 0 !important;
 }
 
-.border-left-0 {
+.border-left-0, .border-start-0 {
   border-left: 0 !important;
 }
 
@@ -19502,7 +19502,7 @@ button.bg-dark:focus {
   border-top-right-radius: 0.25rem !important;
 }
 
-.rounded-right {
+.rounded-right, .rounded-end {
   border-top-right-radius: 0.25rem !important;
   border-bottom-right-radius: 0.25rem !important;
 }
@@ -19512,7 +19512,7 @@ button.bg-dark:focus {
   border-bottom-left-radius: 0.25rem !important;
 }
 
-.rounded-left {
+.rounded-left, .rounded-start {
   border-top-left-radius: 0.25rem !important;
   border-bottom-left-radius: 0.25rem !important;
 }
diff --git a/theme/classic/templates/navbar.mustache b/theme/classic/templates/navbar.mustache
index 1b56b419950..560fd791f3c 100644
--- a/theme/classic/templates/navbar.mustache
+++ b/theme/classic/templates/navbar.mustache
@@ -55,7 +55,7 @@
             {{{ output.page_heading_menu }}}
         </ul>
         <div id="usernavigation" class="navbar-nav my-1 ms-auto">
-            <div class="divider border-left h-50 align-self-center mx-1"></div>
+            <div class="divider border-start h-50 align-self-center mx-1"></div>
             {{{ output.search_box }}}
             {{{ output.navbar_plugin_output }}}
             <div class="d-flex align-items-stretch usermenu-container" data-region="usermenu">