diff --git a/.upgradenotes/MDL-80156-2025021014443873.yml b/.upgradenotes/MDL-80156-2025021014443873.yml
new file mode 100644
index 00000000000..727dae65bda
--- /dev/null
+++ b/.upgradenotes/MDL-80156-2025021014443873.yml
@@ -0,0 +1,5 @@
+issueNumber: MDL-80156
+notes:
+  theme_boost:
+    - message: Remove SCSS deprecated in 4.4
+      type: removed
diff --git a/theme/boost/scss/moodle/deprecated.scss b/theme/boost/scss/moodle/deprecated.scss
index 0b48a22c5d7..eb93b37b0b5 100644
--- a/theme/boost/scss/moodle/deprecated.scss
+++ b/theme/boost/scss/moodle/deprecated.scss
@@ -37,30 +37,6 @@
 //     @include deprecated-styles();
 // }
 
-//
-// Deprecated since Moodle 4.4.
-//
-
-// The .togglecompletion usage was deprecated in 311 and finally removed in 403.
-// Replaced by core_renderer::activity_information() and proper use of templates.
-.path-course-view li.activity form.togglecompletion {
-    @include deprecated-styles();
-}
-.path-course-view li.activity form.togglecompletion .ajaxworking {
-    width: 16px;
-    height: 16px;
-    position: absolute;
-    right: 22px;
-    top: 3px;
-    background: url([[pix:i/ajaxloader]]) no-repeat;
-}
-.path-course-view li.activity form.togglecompletion .btn {
-    padding: 0;
-}
-.path-course-view li.activity form.togglecompletion img {
-    max-width: none; /* The width is 0 so ensure we don't end up with a relative max-width */
-}
-
 //
 // Deprecated since Moodle 5.0.
 //
diff --git a/theme/boost/style/moodle.css b/theme/boost/style/moodle.css
index f0320141438..fb9f324849d 100644
--- a/theme/boost/style/moodle.css
+++ b/theme/boost/style/moodle.css
@@ -38781,41 +38781,6 @@ div.editor_atto_toolbar button .icon {
 /**
  Deprecations
  */
-.path-course-view li.activity form.togglecompletion {
-  /* stylelint-disable declaration-no-important */
-  /* stylelint-enable */
-}
-body.behat-site .path-course-view li.activity form.togglecompletion,
-.path-course-view li.activity form.togglecompletion body.behat-site.path-course-view li.activity form.togglecompletion, body.themedesignermode .path-course-view li.activity form.togglecompletion,
-.path-course-view li.activity form.togglecompletion body.themedesignermode.path-course-view li.activity form.togglecompletion {
-  outline: 3px dotted #ca3120 !important;
-  background-color: #fceeed !important;
-}
-body.behat-site .path-course-view li.activity form.togglecompletion::before,
-.path-course-view li.activity form.togglecompletion body.behat-site.path-course-view li.activity form.togglecompletion::before, body.themedesignermode .path-course-view li.activity form.togglecompletion::before,
-.path-course-view li.activity form.togglecompletion body.themedesignermode.path-course-view li.activity form.togglecompletion::before {
-  content: "Deprecated style in use" !important;
-  color: #ca3120 !important;
-  font-size: smaller !important;
-}
-
-.path-course-view li.activity form.togglecompletion .ajaxworking {
-  width: 16px;
-  height: 16px;
-  position: absolute;
-  right: 22px;
-  top: 3px;
-  background: url([[pix:i/ajaxloader]]) no-repeat;
-}
-
-.path-course-view li.activity form.togglecompletion .btn {
-  padding: 0;
-}
-
-.path-course-view li.activity form.togglecompletion img {
-  max-width: none; /* The width is 0 so ensure we don't end up with a relative max-width */
-}
-
 .course-content .stateready .section .spinner {
   /* stylelint-disable declaration-no-important */
   /* stylelint-enable */
diff --git a/theme/classic/style/moodle.css b/theme/classic/style/moodle.css
index e09da2164e6..6966dc724e5 100644
--- a/theme/classic/style/moodle.css
+++ b/theme/classic/style/moodle.css
@@ -38715,41 +38715,6 @@ div.editor_atto_toolbar button .icon {
 /**
  Deprecations
  */
-.path-course-view li.activity form.togglecompletion {
-  /* stylelint-disable declaration-no-important */
-  /* stylelint-enable */
-}
-body.behat-site .path-course-view li.activity form.togglecompletion,
-.path-course-view li.activity form.togglecompletion body.behat-site.path-course-view li.activity form.togglecompletion, body.themedesignermode .path-course-view li.activity form.togglecompletion,
-.path-course-view li.activity form.togglecompletion body.themedesignermode.path-course-view li.activity form.togglecompletion {
-  outline: 3px dotted #ca3120 !important;
-  background-color: #fceeed !important;
-}
-body.behat-site .path-course-view li.activity form.togglecompletion::before,
-.path-course-view li.activity form.togglecompletion body.behat-site.path-course-view li.activity form.togglecompletion::before, body.themedesignermode .path-course-view li.activity form.togglecompletion::before,
-.path-course-view li.activity form.togglecompletion body.themedesignermode.path-course-view li.activity form.togglecompletion::before {
-  content: "Deprecated style in use" !important;
-  color: #ca3120 !important;
-  font-size: smaller !important;
-}
-
-.path-course-view li.activity form.togglecompletion .ajaxworking {
-  width: 16px;
-  height: 16px;
-  position: absolute;
-  right: 22px;
-  top: 3px;
-  background: url([[pix:i/ajaxloader]]) no-repeat;
-}
-
-.path-course-view li.activity form.togglecompletion .btn {
-  padding: 0;
-}
-
-.path-course-view li.activity form.togglecompletion img {
-  max-width: none; /* The width is 0 so ensure we don't end up with a relative max-width */
-}
-
 .course-content .stateready .section .spinner {
   /* stylelint-disable declaration-no-important */
   /* stylelint-enable */