diff --git a/docs/release-notes/version-4.0.md b/docs/release-notes/version-4.0.md
index e2502df8c..507b8dcdd 100644
--- a/docs/release-notes/version-4.0.md
+++ b/docs/release-notes/version-4.0.md
@@ -2,6 +2,10 @@
 
 ## v4.0.0 (FUTURE)
 
+### Breaking Changes
+
+* The deprecated `device_role` & `device_role_id` filters for devices have been removed. (Use `role` and `role_id` instead.)
+
 ### New Features
 
 #### Complete UI Refresh ([#12128](https://github.com/netbox-community/netbox/issues/12128))
@@ -26,3 +30,5 @@ The NetBox user interface has been completely refreshed and updated.
 * [#14657](https://github.com/netbox-community/netbox/issues/14657) - Remove backward compatibility for old permissions mapping under `ActionsMixin`
 * [#14658](https://github.com/netbox-community/netbox/issues/14658) - Remove backward compatibility for importing `process_webhook()` (now `extras.webhooks.send_webhook()`)
 * [#14740](https://github.com/netbox-community/netbox/issues/14740) - Remove the obsolete `BootstrapMixin` form mixin class
+* [#15099](https://github.com/netbox-community/netbox/issues/15099) - Remove obsolete `device_role` and `device_role_id` filters for devices
+* [#15100](https://github.com/netbox-community/netbox/issues/15100) - Remove obsolete `NullableCharField` class
diff --git a/netbox/dcim/filtersets.py b/netbox/dcim/filtersets.py
index 68edc93f6..4810e9cab 100644
--- a/netbox/dcim/filtersets.py
+++ b/netbox/dcim/filtersets.py
@@ -1288,18 +1288,6 @@ class DeviceComponentFilterSet(django_filters.FilterSet):
         to_field_name='name',
         label=_('Virtual Chassis'),
     )
-    # TODO: Remove in v4.0
-    device_role_id = django_filters.ModelMultipleChoiceFilter(
-        field_name='device__role',
-        queryset=DeviceRole.objects.all(),
-        label=_('Device role (ID)'),
-    )
-    device_role = django_filters.ModelMultipleChoiceFilter(
-        field_name='device__role__slug',
-        queryset=DeviceRole.objects.all(),
-        to_field_name='slug',
-        label=_('Device role (slug)'),
-    )
 
     def search(self, queryset, name, value):
         if not value.strip():
diff --git a/netbox/project-static/dist/netbox.css b/netbox/project-static/dist/netbox.css
index 48a70fd10..e016f0923 100644
Binary files a/netbox/project-static/dist/netbox.css and b/netbox/project-static/dist/netbox.css differ
diff --git a/netbox/project-static/dist/netbox.js b/netbox/project-static/dist/netbox.js
index 50b9ca705..71b1fc774 100644
Binary files a/netbox/project-static/dist/netbox.js and b/netbox/project-static/dist/netbox.js differ
diff --git a/netbox/project-static/dist/netbox.js.map b/netbox/project-static/dist/netbox.js.map
index 431f5e626..8f4dde4e2 100644
Binary files a/netbox/project-static/dist/netbox.js.map and b/netbox/project-static/dist/netbox.js.map differ
diff --git a/netbox/project-static/src/links.ts b/netbox/project-static/src/links.ts
deleted file mode 100644
index d39f3605b..000000000
--- a/netbox/project-static/src/links.ts
+++ /dev/null
@@ -1,15 +0,0 @@
-import { isTruthy, getElements } from './util';
-
-/**
- * Allow any element to be made "clickable" with the use of the `data-href` attribute.
- */
-export function initLinks(): void {
-  for (const link of getElements('*[data-href]')) {
-    const href = link.getAttribute('data-href');
-    if (isTruthy(href)) {
-      link.addEventListener('click', () => {
-        window.location.assign(href);
-      });
-    }
-  }
-}
diff --git a/netbox/project-static/src/netbox.ts b/netbox/project-static/src/netbox.ts
index 8c274c64b..59faab222 100644
--- a/netbox/project-static/src/netbox.ts
+++ b/netbox/project-static/src/netbox.ts
@@ -12,7 +12,6 @@ import { initInterfaceTable } from './tables';
 import { initSideNav } from './sidenav';
 import { initDashboard } from './dashboard';
 import { initRackElevation } from './racks';
-import { initLinks } from './links';
 import { initHtmx } from './htmx';
 
 function initDocument(): void {
@@ -31,7 +30,6 @@ function initDocument(): void {
     initSideNav,
     initDashboard,
     initRackElevation,
-    initLinks,
     initHtmx,
   ]) {
     init();
diff --git a/netbox/project-static/styles/netbox.scss b/netbox/project-static/styles/netbox.scss
index 0fece199b..3afaaa9fc 100644
--- a/netbox/project-static/styles/netbox.scss
+++ b/netbox/project-static/styles/netbox.scss
@@ -5,7 +5,6 @@
 @import '../node_modules/@tabler/core/src/scss/vendor/tom-select';
 
 // Overrides of external libraries
-@import 'overrides/slim-select';
 @import 'overrides/tabler';
 
 // Transitional styling to ease migration of templates from NetBox v3.x
diff --git a/netbox/project-static/styles/overrides/_slim-select.scss b/netbox/project-static/styles/overrides/_slim-select.scss
deleted file mode 100644
index e9f079d44..000000000
--- a/netbox/project-static/styles/overrides/_slim-select.scss
+++ /dev/null
@@ -1,195 +0,0 @@
-// SlimSelect Style Overrides.
-
-$height: $input-height;
-$white: $white;
-$font-color: $input-color;
-$font-placeholder-color: $input-placeholder-color;
-$font-disabled-color: $form-select-disabled-color;
-$primary-color: $primary;
-$border-color: $form-select-border-color;
-$search-highlight-color: $yellow;
-$border-radius: $form-select-border-radius;
-$spacing-l: $input-padding-x;
-$spacing-m: $input-padding-x;
-$spacing-s: $input-padding-x;
-
-:root {
-  // Light Mode Variables.
-  --nbx-select-content-bg: #{$form-select-bg};
-  --nbx-select-option-selected-bg: #{$gray-300};
-  --nbx-select-option-hover-bg: #{$blue};
-  --nbx-select-option-hover-color: #{$white};
-  --nbx-select-placeholder-color: #{$gray-500};
-  --nbx-select-value-color: #{$white};
-  &[data-netbox-color-mode='dark'] {
-    // Dark Mode Variables.
-    --nbx-select-content-bg: #{$gray-900};
-    --nbx-select-option-selected-bg: #{$gray-500};
-    --nbx-select-option-hover-bg: #{$blue-200};
-    --nbx-select-option-hover-color: #{color-contrast($blue-200)};
-    --nbx-select-placeholder-color: #{$gray-700};
-    --nbx-select-value-color: #{$black};
-  }
-}
-
-@import '../node_modules/slim-select/src/slim-select/slimselect';
-
-.ss-main {
-  color: $form-select-color;
-
-  .ss-single-selected,
-  .ss-multi-selected {
-    padding: $form-select-padding-y $input-padding-x $form-select-padding-y $form-select-padding-x;
-    background-color: $form-select-bg;
-    border: $form-select-border-width solid $input-border-color;
-    &[disabled] {
-      color: $form-select-disabled-color;
-      background-color: $form-select-disabled-bg;
-      border-color: $form-select-disabled-border-color;
-    }
-  }
-
-  div.ss-multi-selected .ss-values .ss-disabled,
-  div.ss-single-selected span.placeholder .ss-disabled {
-    color: var(--nbx-select-placeholder-color);
-  }
-
-  .ss-single-selected {
-    span.ss-arrow {
-      // Inherit the arrow color from the parent (see color selector).
-      span.arrow-down,
-      span.arrow-up {
-        border-color: currentColor;
-        color: $text-muted;
-      }
-    }
-    // Don't show the depth indicator outside of the menu.
-    .placeholder .depth {
-      display: none;
-    }
-    span.placeholder > *,
-    span.placeholder {
-      line-height: $input-line-height;
-    }
-  }
-
-  .ss-multi-selected {
-    align-items: center;
-    padding-right: $input-padding-x;
-    padding-left: $input-padding-x;
-
-    .ss-values {
-      .ss-disabled {
-        padding: 4px 0;
-      }
-      .ss-value {
-        color: var(--nbx-select-value-color);
-        border-radius: $badge-border-radius;
-
-        // Don't show the depth indicator outside of the menu.
-        .depth {
-          display: none;
-        }
-      }
-    }
-    .ss-add {
-      margin: 0 0.75rem;
-    }
-  }
-
-  .ss-content {
-    background-color: var(--nbx-select-content-bg);
-    .ss-list {
-      .ss-option {
-        &.ss-option-selected {
-          color: $body-color;
-          background-color: var(--nbx-select-option-selected-bg);
-        }
-
-        &:hover {
-          color: var(--nbx-select-option-hover-color);
-          background-color: var(--nbx-select-option-hover-bg);
-        }
-
-        &:last-child {
-          border-bottom-right-radius: $form-select-border-radius;
-          border-bottom-left-radius: $form-select-border-radius;
-        }
-
-        &.ss-disabled {
-          background-color: unset;
-          &:hover {
-            color: $form-select-disabled-color;
-          }
-        }
-
-        .depth {
-          // Lighten the dash prefix on nested options.
-          opacity: 0.3;
-        }
-      }
-
-      &::-webkit-scrollbar {
-        right: 0;
-        width: 4px;
-        &:hover {
-          opacity: 0.8;
-        }
-      }
-
-      &::-webkit-scrollbar-track {
-        background: transparent;
-      }
-
-      &::-webkit-scrollbar-thumb {
-        right: 0;
-        width: 2px;
-        background-color: var(--nbx-sidebar-scroll);
-      }
-    }
-    border-bottom-right-radius: $form-select-border-radius;
-    border-bottom-left-radius: $form-select-border-radius;
-    .ss-search {
-      padding-right: $spacer * 0.5;
-
-      button {
-        margin-left: $spacer * 0.75;
-      }
-
-      input[type='search'] {
-        color: $input-color;
-        background-color: $form-select-bg;
-        border: $input-border-width solid $input-border-color;
-        &:focus {
-          border-color: $form-select-focus-border-color;
-          outline: 0;
-          @if $enable-shadows {
-            @include box-shadow($form-select-box-shadow, $form-select-focus-box-shadow);
-          } @else {
-            // Avoid using mixin so we can pass custom focus shadow properly
-            box-shadow: $form-select-focus-box-shadow;
-          }
-        }
-      }
-    }
-  }
-}
-
-// Fix slim-select 1.x placeholder styling
-.ss-main {
-	.ss-single-selected {
-		.placeholder {
-			cursor: pointer;
-			opacity: 1;
-			background-color: transparent !important;
-		}
-	}
-}
-
-// Apply red border for fields inside a row with .has-errors
-.has-errors {
-  .ss-single-selected,
-  .ss-multi-selected {
-    border-color: $red;
-  }
-}
diff --git a/netbox/utilities/fields.py b/netbox/utilities/fields.py
index 65e01db81..d2c14c2c7 100644
--- a/netbox/utilities/fields.py
+++ b/netbox/utilities/fields.py
@@ -12,26 +12,10 @@ __all__ = (
     'ColorField',
     'CounterCacheField',
     'NaturalOrderingField',
-    'NullableCharField',
     'RestrictedGenericForeignKey',
 )
 
 
-# Deprecated: Retained only to ensure successful migration from early releases
-# Use models.CharField(null=True) instead
-# TODO: Remove in v4.0
-class NullableCharField(models.CharField):
-    description = "Stores empty values as NULL rather than ''"
-
-    def to_python(self, value):
-        if isinstance(value, models.CharField):
-            return value
-        return value or ''
-
-    def get_prep_value(self, value):
-        return value or None
-
-
 class ColorField(models.CharField):
     default_validators = [ColorValidator]
     description = "A hexadecimal RGB color code"