Remove $govuk-use-legacy-font and $govuk-font-family-tabular settings

src/govuk/helpers/_typography.scss

@@ -184,17 +184,11 @@
 
 @mixin govuk-font($size, $weight: regular, $tabular: false, $line-height: false) {
   @if $tabular {
-    // if govuk-font-family-tabular is set use $govuk-font-family-tabular
-    @if $govuk-font-family-tabular {
-      @include govuk-typography-common($font-family: $govuk-font-family-tabular);
-    } @else {
-      @include govuk-typography-common;
-      font-feature-settings: "tnum" 1;
-
-      @supports (font-variant-numeric: tabular-nums) {
-        font-feature-settings: normal;
-        font-variant-numeric: tabular-nums;
-      }
+    @include govuk-typography-common;
+    font-feature-settings: "tnum" 1;
+    @supports (font-variant-numeric: tabular-nums) {
+      font-feature-settings: normal;
+      font-variant-numeric: tabular-nums;
     }
   } @else {
     @include govuk-typography-common;

src/govuk/settings/_typography-font-families.scss

@@ -9,24 +9,3 @@
 /// @access public
 
 $govuk-font-family-gds-transport: "GDS Transport", arial, sans-serif;
-
-/// List of font families to use if using NTA (old font 'stack' for
-/// GOV.UK)
-///
-/// @type List
-/// @access public
-/// @deprecated To be removed once support for compatibility mode is dropped
-
-$govuk-font-family-nta: "nta", arial, sans-serif;
-
-/// List of font families to use if using the 'tabular numbers' subset of NTA
-/// (the default font 'stack' for GOV.UK)
-///
-/// Because ntatabularnumbers only includes the digits 0-10, all other glyphs
-/// will 'fall-through' the stack to NTA.
-///
-/// @type List
-/// @access public
-/// @deprecated To be removed once support for compatibility mode is dropped
-
-$govuk-font-family-nta-tabular: "ntatabularnumbers", $govuk-font-family-nta;

src/govuk/settings/_typography-font.scss

@@ -1,42 +1,9 @@
-@import "compatibility";
 @import "typography-font-families";
 
 ////
 /// @group settings/typography
 ////
 
-/// Use 'legacy' fonts
-///
-/// Whether or not to use v1 nta font from GOV.UK Elements / Frontend
-/// Toolkit, for teams that are migrating to GOV.UK Frontend and may be using
-/// components from both places in a single application.
-///
-/// @type Boolean
-/// @access public
-/// @deprecated Will be removed in v5.0 with the rest of the compatibility mode
-/// suite of tools and settings
-
-$govuk-use-legacy-font: if(
-  (
-    $govuk-compatibility-govukfrontendtoolkit or
-    $govuk-compatibility-govuktemplate or
-    $govuk-compatibility-govukelements
-  ),
-  true,
-  false
-) !default;
-
-// Only show the deprecation warning if user is setting $govuk-use-legacy-font
-// manually instead of automatically via compatibility variables
-@if $govuk-use-legacy-font == true and
-  $govuk-compatibility-govukfrontendtoolkit == false and
-  $govuk-compatibility-govuktemplate == false and
-  $govuk-compatibility-govukelements == false {
-  @include _warning(legacy-font, "$govuk-use-legacy-font is deprecated. " +
-  "From version 5.0, GOV.UK Frontend will only support the included version " +
-  "of GDS Transport.");
-}
-
 // =========================================================
 // Font families
 // =========================================================
@@ -46,32 +13,7 @@ $govuk-use-legacy-font: if(
 /// @type List
 /// @access public
 
-$govuk-font-family: if(
-  $govuk-use-legacy-font,
-  $govuk-font-family-nta,
-  $govuk-font-family-gds-transport
-) !default;
-
-/// Font families to use when displaying tabular numbers
-///
-/// @type List
-/// @access public
-/// @deprecated Will be removed in v5.0 with the rest of the compatibility mode
-/// suite of tools and settings
-
-$govuk-font-family-tabular: if(
-  $govuk-use-legacy-font,
-  $govuk-font-family-nta-tabular,
-  false
-) !default;
-
-// Only show the deprecation warning if user is setting $govuk-font-family-tabular
-// manually instead of automatically via $govuk-use-legacy-font
-@if $govuk-font-family-tabular != false and $govuk-use-legacy-font == false {
-  @include _warning(tabular-font-face, "$govuk-font-family-tabular is deprecated. " +
-  "From version 5.0, GOV.UK Frontend will not support using a separate " +
-  "font-face for tabular numbers.");
-}
+$govuk-font-family: $govuk-font-family-gds-transport !default;
 
 /// Font families to use for print media
 ///