diff --git a/CHANGELOG.md b/CHANGELOG.md
index 928c8d87f3..54b810597c 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,13 @@
 # Changelog
 
+## 3.4.3 (non-ruby only)
+
+* Fix malformed `math.div` expressions. [#1225](https://github.com/twbs/bootstrap-sass/pull/1225)
+
+## 3.4.2 (non-ruby only)
+
+* Compatibility with Sass 1.33. [#1221](https://github.com/twbs/bootstrap-sass/pull/1221)
+
 ## 3.4.0
 
 * Bootstrap rubygem now depends on SassC instead of Sass.
diff --git a/assets/javascripts/bootstrap-sprockets.js b/assets/javascripts/bootstrap-sprockets.js
index 37468b35d4..fb01d63f04 100644
--- a/assets/javascripts/bootstrap-sprockets.js
+++ b/assets/javascripts/bootstrap-sprockets.js
@@ -1,12 +1,12 @@
-//= require ./bootstrap/affix
+//= require ./bootstrap/transition
 //= require ./bootstrap/alert
 //= require ./bootstrap/button
 //= require ./bootstrap/carousel
 //= require ./bootstrap/collapse
 //= require ./bootstrap/dropdown
 //= require ./bootstrap/modal
-//= require ./bootstrap/scrollspy
 //= require ./bootstrap/tab
-//= require ./bootstrap/transition
+//= require ./bootstrap/affix
+//= require ./bootstrap/scrollspy
 //= require ./bootstrap/tooltip
 //= require ./bootstrap/popover
diff --git a/assets/stylesheets/bootstrap/_carousel.scss b/assets/stylesheets/bootstrap/_carousel.scss
index 52a1f7bff0..684360ff88 100644
--- a/assets/stylesheets/bootstrap/_carousel.scss
+++ b/assets/stylesheets/bootstrap/_carousel.scss
@@ -1,3 +1,4 @@
+@use "sass:math";
 //
 // Carousel
 // --------------------------------------------------
@@ -244,16 +245,16 @@
     .icon-next {
       width: ($carousel-control-font-size * 1.5);
       height: ($carousel-control-font-size * 1.5);
-      margin-top: ($carousel-control-font-size / -2);
+      margin-top: math.div($carousel-control-font-size, -2);
       font-size: ($carousel-control-font-size * 1.5);
     }
     .glyphicon-chevron-left,
     .icon-prev {
-      margin-left: ($carousel-control-font-size / -2);
+      margin-left: math.div($carousel-control-font-size, -2);
     }
     .glyphicon-chevron-right,
     .icon-next {
-      margin-right: ($carousel-control-font-size / -2);
+      margin-right: math.div($carousel-control-font-size, -2);
     }
   }
 
diff --git a/assets/stylesheets/bootstrap/_code.scss b/assets/stylesheets/bootstrap/_code.scss
index 8e2b2a7f43..6299ddbf3f 100644
--- a/assets/stylesheets/bootstrap/_code.scss
+++ b/assets/stylesheets/bootstrap/_code.scss
@@ -1,3 +1,4 @@
+@use "sass:math";
 //
 // Code (inline and block)
 // --------------------------------------------------
@@ -40,8 +41,8 @@ kbd {
 // Blocks of code
 pre {
   display: block;
-  padding: (($line-height-computed - 1) / 2);
-  margin: 0 0 ($line-height-computed / 2);
+  padding: math.div(($line-height-computed - 1), 2);
+  margin: 0 0 math.div($line-height-computed, 2);
   font-size: ($font-size-base - 1); // 14px to 13px
   line-height: $line-height-base;
   color: $pre-color;
diff --git a/assets/stylesheets/bootstrap/_forms.scss b/assets/stylesheets/bootstrap/_forms.scss
index d2e2bac5cd..00951b3f27 100644
--- a/assets/stylesheets/bootstrap/_forms.scss
+++ b/assets/stylesheets/bootstrap/_forms.scss
@@ -1,3 +1,4 @@
+@use "sass:math";
 //
 // Forms
 // --------------------------------------------------
@@ -581,7 +582,7 @@ textarea.form-control {
   // Reposition the icon because it's now within a grid column and columns have
   // `position: relative;` on them. Also accounts for the grid gutter padding.
   .has-feedback .form-control-feedback {
-    right: floor(($grid-gutter-width / 2));
+    right: floor(math.div($grid-gutter-width, 2));
   }
 
   // Form group sizes
diff --git a/assets/stylesheets/bootstrap/_jumbotron.scss b/assets/stylesheets/bootstrap/_jumbotron.scss
index 7215b99131..07a0f98ff7 100644
--- a/assets/stylesheets/bootstrap/_jumbotron.scss
+++ b/assets/stylesheets/bootstrap/_jumbotron.scss
@@ -1,3 +1,4 @@
+@use "sass:math";
 //
 // Jumbotron
 // --------------------------------------------------
@@ -16,7 +17,7 @@
   }
 
   p {
-    margin-bottom: ($jumbotron-padding / 2);
+    margin-bottom: math.div($jumbotron-padding, 2);
     font-size: $jumbotron-font-size;
     font-weight: 200;
   }
@@ -27,8 +28,8 @@
 
   .container &,
   .container-fluid & {
-    padding-right: ($grid-gutter-width / 2);
-    padding-left: ($grid-gutter-width / 2);
+    padding-right: math.div($grid-gutter-width, 2);
+    padding-left: math.div($grid-gutter-width, 2);
     border-radius: $border-radius-large; // Only round corners at higher resolutions if contained in a container
   }
 
diff --git a/assets/stylesheets/bootstrap/_navbar.scss b/assets/stylesheets/bootstrap/_navbar.scss
index 5d9093a93c..135aba0aed 100644
--- a/assets/stylesheets/bootstrap/_navbar.scss
+++ b/assets/stylesheets/bootstrap/_navbar.scss
@@ -1,3 +1,4 @@
+@use "sass:math";
 //
 // Navbars
 // --------------------------------------------------
@@ -228,7 +229,7 @@
 // the nav the full height of the horizontal nav (above 768px).
 
 .navbar-nav {
-  margin: ($navbar-padding-vertical / 2) (-$navbar-padding-horizontal);
+  margin: math.div($navbar-padding-vertical, 2) (-$navbar-padding-horizontal);
 
   > li > a {
     padding-top: 10px;
diff --git a/assets/stylesheets/bootstrap/_type.scss b/assets/stylesheets/bootstrap/_type.scss
index c63cc4c071..ac2eccdc97 100644
--- a/assets/stylesheets/bootstrap/_type.scss
+++ b/assets/stylesheets/bootstrap/_type.scss
@@ -1,3 +1,4 @@
+@use "sass:math";
 //
 // Typography
 // --------------------------------------------------
@@ -25,7 +26,7 @@ h1, .h1,
 h2, .h2,
 h3, .h3 {
   margin-top: $line-height-computed;
-  margin-bottom: ($line-height-computed / 2);
+  margin-bottom: math.div($line-height-computed, 2);
 
   small,
   .small {
@@ -35,8 +36,8 @@ h3, .h3 {
 h4, .h4,
 h5, .h5,
 h6, .h6 {
-  margin-top: ($line-height-computed / 2);
-  margin-bottom: ($line-height-computed / 2);
+  margin-top: math.div($line-height-computed, 2);
+  margin-bottom: math.div($line-height-computed, 2);
 
   small,
   .small {
@@ -56,7 +57,7 @@ h6, .h6 { font-size: $font-size-h6; }
 // -------------------------
 
 p {
-  margin: 0 0 ($line-height-computed / 2);
+  margin: 0 0 math.div($line-height-computed, 2);
 }
 
 .lead {
@@ -74,10 +75,10 @@ p {
 // Emphasis & misc
 // -------------------------
 
-// Ex: (12px small font / 14px base font) * 100% = about 85%
+// Ex: math.div(12px small font, 14px base font) * 100% = about 85%
 small,
 .small {
-  font-size: floor((100% * $font-size-small / $font-size-base));
+  font-size: floor(math.div(100% * $font-size-small, $font-size-base));
 }
 
 mark,
@@ -136,7 +137,7 @@ mark,
 // -------------------------
 
 .page-header {
-  padding-bottom: (($line-height-computed / 2) - 1);
+  padding-bottom: (math.div($line-height-computed, 2) - 1);
   margin: ($line-height-computed * 2) 0 $line-height-computed;
   border-bottom: 1px solid $page-header-border-color;
 }
@@ -149,7 +150,7 @@ mark,
 ul,
 ol {
   margin-top: 0;
-  margin-bottom: ($line-height-computed / 2);
+  margin-bottom: math.div($line-height-computed, 2);
   ul,
   ol {
     margin-bottom: 0;
@@ -239,7 +240,7 @@ abbr[data-original-title] {
 
 // Blockquotes
 blockquote {
-  padding: ($line-height-computed / 2) $line-height-computed;
+  padding: math.div($line-height-computed, 2) $line-height-computed;
   margin: 0 0 $line-height-computed;
   font-size: $blockquote-font-size;
   border-left: 5px solid $blockquote-border-color;
diff --git a/assets/stylesheets/bootstrap/_variables.scss b/assets/stylesheets/bootstrap/_variables.scss
index 898ef14adc..02fe1f43b7 100644
--- a/assets/stylesheets/bootstrap/_variables.scss
+++ b/assets/stylesheets/bootstrap/_variables.scss
@@ -1,4 +1,5 @@
 $bootstrap-sass-asset-helper: false !default;
+@use "sass:math";
 //
 // Variables
 // --------------------------------------------------
@@ -365,8 +366,8 @@ $container-lg:                 $container-large-desktop !default;
 $navbar-height:                    50px !default;
 $navbar-margin-bottom:             $line-height-computed !default;
 $navbar-border-radius:             $border-radius-base !default;
-$navbar-padding-horizontal:        floor(($grid-gutter-width / 2)) !default;
-$navbar-padding-vertical:          (($navbar-height - $line-height-computed) / 2) !default;
+$navbar-padding-horizontal:        floor(math.div($grid-gutter-width, 2)) !default;
+$navbar-padding-vertical:          math.div(($navbar-height - $line-height-computed), 2) !default;
 $navbar-collapse-max-height:       340px !default;
 
 $navbar-default-color:             #777 !default;
diff --git a/assets/stylesheets/bootstrap/mixins/_grid-framework.scss b/assets/stylesheets/bootstrap/mixins/_grid-framework.scss
index 2b84cb13c8..6160a048e3 100644
--- a/assets/stylesheets/bootstrap/mixins/_grid-framework.scss
+++ b/assets/stylesheets/bootstrap/mixins/_grid-framework.scss
@@ -1,3 +1,4 @@
+@use "sass:math";
 // Framework grid generation
 //
 // Used only by Bootstrap to generate the correct number of grid classes given
@@ -13,8 +14,8 @@
     // Prevent columns from collapsing when empty
     min-height: 1px;
     // Inner gutter via padding
-    padding-right: floor(($grid-gutter-width / 2));
-    padding-left: ceil(($grid-gutter-width / 2));
+    padding-right: floor(math.div($grid-gutter-width, 2));
+    padding-left: ceil(math.div($grid-gutter-width, 2));
   }
 }
 
@@ -33,12 +34,12 @@
 @mixin calc-grid-column($index, $class, $type) {
   @if ($type == width) and ($index > 0) {
     .col-#{$class}-#{$index} {
-      width: percentage(($index / $grid-columns));
+      width: percentage(math.div($index, $grid-columns));
     }
   }
   @if ($type == push) and ($index > 0) {
     .col-#{$class}-push-#{$index} {
-      left: percentage(($index / $grid-columns));
+      left: percentage(math.div($index, $grid-columns));
     }
   }
   @if ($type == push) and ($index == 0) {
@@ -48,7 +49,7 @@
   }
   @if ($type == pull) and ($index > 0) {
     .col-#{$class}-pull-#{$index} {
-      right: percentage(($index / $grid-columns));
+      right: percentage(math.div($index, $grid-columns));
     }
   }
   @if ($type == pull) and ($index == 0) {
@@ -58,7 +59,7 @@
   }
   @if ($type == offset) {
     .col-#{$class}-offset-#{$index} {
-      margin-left: percentage(($index / $grid-columns));
+      margin-left: percentage(math.div($index, $grid-columns));
     }
   }
 }
diff --git a/assets/stylesheets/bootstrap/mixins/_grid.scss b/assets/stylesheets/bootstrap/mixins/_grid.scss
index 884ac4f5b0..0cee189a97 100644
--- a/assets/stylesheets/bootstrap/mixins/_grid.scss
+++ b/assets/stylesheets/bootstrap/mixins/_grid.scss
@@ -1,11 +1,12 @@
+@use "sass:math";
 // Grid system
 //
 // Generate semantic grid columns with these mixins.
 
 // Centered container element
 @mixin container-fixed($gutter: $grid-gutter-width) {
-  padding-right: ceil(($gutter / 2));
-  padding-left: floor(($gutter / 2));
+  padding-right: ceil(math.div($gutter, 2));
+  padding-left: floor(math.div($gutter, 2));
   margin-right: auto;
   margin-left: auto;
   @include clearfix;
@@ -13,8 +14,8 @@
 
 // Creates a wrapper for a series of columns
 @mixin make-row($gutter: $grid-gutter-width) {
-  margin-right: floor(($gutter / -2));
-  margin-left: ceil(($gutter / -2));
+  margin-right: floor(math.div($gutter, -2));
+  margin-left: ceil(math.div($gutter, -2));
   @include clearfix;
 }
 
@@ -22,46 +23,46 @@
 @mixin make-xs-column($columns, $gutter: $grid-gutter-width) {
   position: relative;
   float: left;
-  width: percentage(($columns / $grid-columns));
+  width: percentage(math.div($columns, $grid-columns));
   min-height: 1px;
-  padding-right: ($gutter / 2);
-  padding-left: ($gutter / 2);
+  padding-right: math.div($gutter, 2);
+  padding-left: math.div($gutter, 2);
 }
 @mixin make-xs-column-offset($columns) {
-  margin-left: percentage(($columns / $grid-columns));
+  margin-left: percentage(math.div($columns, $grid-columns));
 }
 @mixin make-xs-column-push($columns) {
-  left: percentage(($columns / $grid-columns));
+  left: percentage(math.div($columns, $grid-columns));
 }
 @mixin make-xs-column-pull($columns) {
-  right: percentage(($columns / $grid-columns));
+  right: percentage(math.div($columns, $grid-columns));
 }
 
 // Generate the small columns
 @mixin make-sm-column($columns, $gutter: $grid-gutter-width) {
   position: relative;
   min-height: 1px;
-  padding-right: ($gutter / 2);
-  padding-left: ($gutter / 2);
+  padding-right: math.div($gutter, 2);
+  padding-left: math.div($gutter, 2);
 
   @media (min-width: $screen-sm-min) {
     float: left;
-    width: percentage(($columns / $grid-columns));
+    width: percentage(math.div($columns, $grid-columns));
   }
 }
 @mixin make-sm-column-offset($columns) {
   @media (min-width: $screen-sm-min) {
-    margin-left: percentage(($columns / $grid-columns));
+    margin-left: percentage(math.div($columns, $grid-columns));
   }
 }
 @mixin make-sm-column-push($columns) {
   @media (min-width: $screen-sm-min) {
-    left: percentage(($columns / $grid-columns));
+    left: percentage(math.div($columns, $grid-columns));
   }
 }
 @mixin make-sm-column-pull($columns) {
   @media (min-width: $screen-sm-min) {
-    right: percentage(($columns / $grid-columns));
+    right: percentage(math.div($columns, $grid-columns));
   }
 }
 
@@ -69,27 +70,27 @@
 @mixin make-md-column($columns, $gutter: $grid-gutter-width) {
   position: relative;
   min-height: 1px;
-  padding-right: ($gutter / 2);
-  padding-left: ($gutter / 2);
+  padding-right: math.div($gutter, 2);
+  padding-left: math.div($gutter, 2);
 
   @media (min-width: $screen-md-min) {
     float: left;
-    width: percentage(($columns / $grid-columns));
+    width: percentage(math.div($columns, $grid-columns));
   }
 }
 @mixin make-md-column-offset($columns) {
   @media (min-width: $screen-md-min) {
-    margin-left: percentage(($columns / $grid-columns));
+    margin-left: percentage(math.div($columns, $grid-columns));
   }
 }
 @mixin make-md-column-push($columns) {
   @media (min-width: $screen-md-min) {
-    left: percentage(($columns / $grid-columns));
+    left: percentage(math.div($columns, $grid-columns));
   }
 }
 @mixin make-md-column-pull($columns) {
   @media (min-width: $screen-md-min) {
-    right: percentage(($columns / $grid-columns));
+    right: percentage(math.div($columns, $grid-columns));
   }
 }
 
@@ -97,26 +98,26 @@
 @mixin make-lg-column($columns, $gutter: $grid-gutter-width) {
   position: relative;
   min-height: 1px;
-  padding-right: ($gutter / 2);
-  padding-left: ($gutter / 2);
+  padding-right: math.div($gutter, 2);
+  padding-left: math.div($gutter, 2);
 
   @media (min-width: $screen-lg-min) {
     float: left;
-    width: percentage(($columns / $grid-columns));
+    width: percentage(math.div($columns, $grid-columns));
   }
 }
 @mixin make-lg-column-offset($columns) {
   @media (min-width: $screen-lg-min) {
-    margin-left: percentage(($columns / $grid-columns));
+    margin-left: percentage(math.div($columns, $grid-columns));
   }
 }
 @mixin make-lg-column-push($columns) {
   @media (min-width: $screen-lg-min) {
-    left: percentage(($columns / $grid-columns));
+    left: percentage(math.div($columns, $grid-columns));
   }
 }
 @mixin make-lg-column-pull($columns) {
   @media (min-width: $screen-lg-min) {
-    right: percentage(($columns / $grid-columns));
+    right: percentage(math.div($columns, $grid-columns));
   }
 }
diff --git a/assets/stylesheets/bootstrap/mixins/_nav-divider.scss b/assets/stylesheets/bootstrap/mixins/_nav-divider.scss
index 2e6da02a47..80a39d43ad 100644
--- a/assets/stylesheets/bootstrap/mixins/_nav-divider.scss
+++ b/assets/stylesheets/bootstrap/mixins/_nav-divider.scss
@@ -1,10 +1,11 @@
+@use "sass:math";
 // Horizontal dividers
 //
 // Dividers (basically an hr) within dropdowns and nav lists
 
 @mixin nav-divider($color: #e5e5e5) {
   height: 1px;
-  margin: (($line-height-computed / 2) - 1) 0;
+  margin: (math.div($line-height-computed, 2) - 1) 0;
   overflow: hidden;
   background-color: $color;
 }
diff --git a/assets/stylesheets/bootstrap/mixins/_nav-vertical-align.scss b/assets/stylesheets/bootstrap/mixins/_nav-vertical-align.scss
index c8fbf1a7d6..146d9961c4 100644
--- a/assets/stylesheets/bootstrap/mixins/_nav-vertical-align.scss
+++ b/assets/stylesheets/bootstrap/mixins/_nav-vertical-align.scss
@@ -1,9 +1,10 @@
+@use "sass:math";
 // Navbar vertical align
 //
 // Vertically center elements in the navbar.
 // Example: an element has a height of 30px, so write out `.navbar-vertical-align(30px);` to calculate the appropriate top margin.
 
 @mixin navbar-vertical-align($element-height) {
-  margin-top: (($navbar-height - $element-height) / 2);
-  margin-bottom: (($navbar-height - $element-height) / 2);
+  margin-top: math.div(($navbar-height - $element-height), 2);
+  margin-bottom: math.div(($navbar-height - $element-height), 2);
 }
diff --git a/package.json b/package.json
index d947d8f9a5..88f432110d 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "bootstrap-sass",
-  "version": "3.4.1",
+  "version": "3.4.3",
   "description": "bootstrap-sass is a Sass-powered version of Bootstrap 3, ready to drop right into your Sass powered applications.",
   "main": "assets/javascripts/bootstrap.js",
   "style": "assets/stylesheets/_bootstrap.scss",
@@ -33,7 +33,7 @@
     "url": "https://github.com/twbs/bootstrap-sass/issues"
   },
   "devDependencies": {
-    "node-sass": "^4.9.3",
+    "sass": "^1.33",
     "mincer": "~1.4.0",
     "ejs": "~2.6.1"
   },
diff --git a/tasks/converter/less_conversion.rb b/tasks/converter/less_conversion.rb
index c6cd7e03de..d87a6d0d6a 100644
--- a/tasks/converter/less_conversion.rb
+++ b/tasks/converter/less_conversion.rb
@@ -173,6 +173,7 @@ def convert_to_scss(file)
       file   = replace_calculation_semantics(file)
       file   = replace_file_imports(file)
       file   = wrap_at_groups_with_at_root(file)
+      file   = replace_division(file)
       file
     end
 
@@ -182,6 +183,44 @@ def wrap_at_groups_with_at_root(file)
       }
     end
 
+    def replace_division(less)
+      re = %r{
+        (?<expression>
+          (?<callee>[[:alpha:]\.]+)?
+          \(
+            (?:
+              (?>
+                (?<dividend>
+                  [^()/]+
+                  |
+                  \([^/]+\)
+                )
+                \s+
+                /
+                \s+
+                (?<divisor>
+                  [^()/]+
+                  |
+                  \([^/]+\)
+                )
+              )
+              |
+              \g<expression>
+            )
+          \)
+        )
+      }x
+      return less if less !~ re
+      "@use \"sass:math\";\n" + less.gsub(re) do
+        named_captures = $~.named_captures
+        callee = named_captures['callee']
+        dividend = named_captures['dividend']
+        divisor = named_captures['divisor']
+        expression = "math.div(#{dividend}, #{divisor})"
+        callee.nil? ? expression : "#{callee}(#{expression})"
+      end
+    end
+
     def sass_fn_exists(fn)
       %Q{(#{fn}("") != unquote('#{fn}("")'))}
     end
@@ -691,13 +730,13 @@ def open_brace_pos(css, from, depth = 0)
       from - s.pos + 1
     end
 
-    # insert substitutions into text at positions (Range or Fixnum)
+    # insert substitutions into text at positions (Range or Integer)
     # substitutions can be passed as array or as yields from the &block called with |substring, position, text|
     # position is a range (begin..end)
     def replace_substrings_at(text, positions, replacements = nil, &block)
       offset = 0
       positions.each_with_index do |p, i|
-        p       = (p...p) if p.is_a?(Fixnum)
+        p       = (p...p) if p.is_a?(Integer)
         from    = p.begin + offset
         to      = p.end + offset
         p       = p.exclude_end? ? (from...to) : (from..to)
diff --git a/tasks/converter/network.rb b/tasks/converter/network.rb
index aa62be5e3e..cef78d4377 100644
--- a/tasks/converter/network.rb
+++ b/tasks/converter/network.rb
@@ -19,7 +19,7 @@ def read_files(path, files)
       log_http_get_files files, full_path, false
       files.map do |name|
         Thread.start {
-          contents[name] = open("#{full_path}/#{name}").read
+          contents[name] = URI.open("#{full_path}/#{name}").read
           Thread.exclusive { write_cached_files path, name => contents[name] }
         }
       end.each(&:join)
@@ -56,7 +56,7 @@ def get_file(url)
         File.read(cache_path, mode: 'rb')
       else
         log_http_get_file url, false
-        content = open(url).read
+        content = URI.open(url).read
         File.open(cache_path, 'wb') { |f| f.write content }
         content
       end
diff --git a/templates/project/_bootstrap-variables.sass b/templates/project/_bootstrap-variables.sass
index 8777e1149c..d5bc1a14fa 100644
--- a/templates/project/_bootstrap-variables.sass
+++ b/templates/project/_bootstrap-variables.sass
@@ -1,5 +1,6 @@
-// Override Bootstrap variables here (defaults from bootstrap-sass v3.4.0):
+// Override Bootstrap variables here (defaults from bootstrap-sass v3.4.1):
 
+@use "sass:math";
 //
 // Variables
 // --------------------------------------------------
@@ -366,8 +367,8 @@
 // $navbar-height:                    50px
 // $navbar-margin-bottom:             $line-height-computed
 // $navbar-border-radius:             $border-radius-base
-// $navbar-padding-horizontal:        floor(($grid-gutter-width / 2))
-// $navbar-padding-vertical:          (($navbar-height - $line-height-computed) / 2)
+// $navbar-padding-horizontal:        floor(math.div($grid-gutter-width, 2))
+// $navbar-padding-vertical:          math.div(($navbar-height - $line-height-computed), 2)
 // $navbar-collapse-max-height:       340px
 
 // $navbar-default-color:             #777