diff --git a/config.rb b/config.rb
index 5b0c57402..d8ba7d553 100644
--- a/config.rb
+++ b/config.rb
@@ -71,6 +71,11 @@
   redirect "d/#{basename}.html", to: "/documentation/breaking-changes/#{basename}"
 end
 
+for url in %w[d/random-with-units documentation/breaking-changes/random-with-units
+    d/breaking-changes/color-units documentation/breaking-changes/color-units] do
+  redirect url, to: "/documentation/breaking-changes/function-units"
+end
+
 redirect 'tutorial.html', to: '/guide'
 redirect 'download.html', to: '/install'
 redirect 'try.html', to: 'https://www.sassmeister.com'
diff --git a/source/documentation/breaking-changes.html.md.erb b/source/documentation/breaking-changes.html.md.erb
index 10da4a7f7..7ca5807dc 100644
--- a/source/documentation/breaking-changes.html.md.erb
+++ b/source/documentation/breaking-changes.html.md.erb
@@ -23,18 +23,15 @@ time-sensitive, so they may be released with new minor version numbers instead.
 
 These breaking changes are coming soon or have recently been released:
 
-* [`random()` with units](breaking-changes/random-with-units) beginning in Dart
-  Sass 1.54.5.
+* [Functions are stricter about which units they
+  allow](breaking-changes/function-units) beginning in Dart Sass 1.32.0.
 
-* [Selectors with invalid combinators will be
+* [Selectors with invalid combinators are
   invalid](breaking-changes/bogus-combinators) beginning in Dart Sass 1.54.0.
 
 * [`/` is changing from a division operation to a list
   separator](breaking-changes/slash-div) beginning in Dart Sass 1.33.0.
 
-* [Color functions are becoming more strict about
-  units](breaking-changes/color-units) beginning in Dart Sass 1.32.0.
-
 * [Parsing the special syntax of `@-moz-document` will be
   invalid](breaking-changes/moz-document) beginning in Dart Sass 1.7.2.
 
diff --git a/source/documentation/breaking-changes/color-units.md.erb b/source/documentation/breaking-changes/color-units.md.erb
deleted file mode 100644
index aad47a506..000000000
--- a/source/documentation/breaking-changes/color-units.md.erb
+++ /dev/null
@@ -1,79 +0,0 @@
----
-title: "Breaking Change: Color Units"
-introduction: >
-  In CSS, saturation and lightness parameters always require `%` units and hue
-  parameters allow any angle unit. Sass has historically ignored units for these
-  functions. We're in the process of changing that.
----
-
-It's important that we keep Sass's implementation of [`hsl()`] consistent with
-the CSS spec, and that we keep other Sass functions that deal with colors
-consistent with `hsl()`. One notable place where Sass has historically differed
-from the spec is the way that `hsl()` (and other color functions) handled units.
-
-[`hsl()`]: ../modules#hsl
-
-For hue, CSS allows any [angle unit][] (`deg`, `grad`, `rad`, or `turn`). It
-also allows a unitless number, which is interpreted as `deg`. Historically, Sass
-has allowed *any* unit, and interpreted it as `deg`. This is particularly
-problematic because it meant that the valid CSS expression `hsl(0.5turn, 100%,
-50%)` would be allowed by Sass but interpreted entirely wrong.
-
-[angle unit]: https://drafts.csswg.org/css-values-4/#angles
-
-For lightness and saturation, CSS only allows `%` units. Even unitless numbers
-aren't allowed (unlike for the hue). Historically, Sass has allowed *any* unit,
-and interpreted it as `%`. You could even write `hsl(0, 100px, 50s)` and Sass
-would return the color `red`.
-
-To fix this issue and bring Sass in line with the CSS spec, we're making changes
-in multiple phases: 
-
-## Phase 1
-
-<% impl_status dart: '1.32.0', libsass: false, ruby: false %>
-
-To begin with, we're just introducing deprecation warnings for behaviors that we
-plan to change. Specifically, Sass will emit a deprecation warning if you do any
-of the following:
-
-* Pass a number with a unit other than `deg` as a hue to any function. Passing a
-  unitless number is still allowed.
-
-* Pass a unitless number as saturation or lightness to any function.
-
-* Pass a number with a unit other than `%` as saturation or lightness to any
-  function.
-
-Of these warnings, the first is the most important one to deal with immediately
-specifically if you're passing a number with unit `grad`, `rad`, or `turn`. This
-case will change behavior in Phase 2, which could change how your stylesheets
-render if you don't update them.
-
-## Phase 2
-
-<% impl_status dart: false, libsass: false, ruby: false %>
-
-At least three months after the launch of Phase 1, we'll change the way angle
-units are handled for hue parameters to match the CSS spec. This means that
-numbers with `grad`, `rad`, or `turn` units will be converted to `deg`:
-`0.5turn` will be converted to `180deg`, `100grad` will be converted to `90deg`,
-and so on.
-
-Because this change is necessary to preserve CSS compatibility, according to the
-[Dart Sass compatibility policy] it will be made with only a minor version bump.
-However, it changes as little behavior as possible to ensure that Sass
-interprets all valid CSS according to the CSS spec. All other deprecated
-behavior will remain in place until Phase 3.
-
-[Dart Sass compatibility policy]: https://github.com/sass/dart-sass#compatibility-policy
-
-## Phase 3
-
-<% impl_status dart: false, libsass: false, ruby: false %>
-
-Finally, we'll remove all deprecated behavior by making color functions throw
-errors if they're passed any units that produced deprecation warnings in Phase
-1. Because this is a breaking change that's not strictly necessary for CSS
-compatibility, we'll land it as part of Dart Sass 2.0.0 (which we have no
-immediate plans to release).
diff --git a/source/documentation/breaking-changes/function-units.md.erb b/source/documentation/breaking-changes/function-units.md.erb
new file mode 100644
index 000000000..1194d6601
--- /dev/null
+++ b/source/documentation/breaking-changes/function-units.md.erb
@@ -0,0 +1,208 @@
+---
+title: "Breaking Change: Strict Function Units"
+introduction: >
+  Various built-in functions will become stricter in which units they allow
+  and will handle those units more consistently. This makes Sass more compatible
+  with the CSS spec and helps catch errors more quickly.
+---
+
+## Hue
+
+<% impl_status dart: '1.32.0', libsass: false, ruby: false %>
+
+When specifying a color's hue, CSS allows any [angle unit] (`deg`, `grad`,
+`rad`, or `turn`). It also allows a unitless number, which is interpreted as
+`deg`. Historically, Sass has allowed *any* unit, and interpreted it as `deg`.
+This is particularly problematic because it meant that the valid CSS expression
+`hsl(0.5turn, 100%, 50%)` would be allowed by Sass but interpreted entirely
+wrong.
+
+To fix this issue and bring Sass in line with the CSS spec, we're making changes
+in multiple phases:
+
+### Phase 1
+
+<% impl_status dart: '1.32.0', libsass: false, ruby: false %>
+
+At first, Sass just emitted a deprecation warning if you passed a number with a
+unit other than `deg` as a hue to any function. Passing a unitless number was
+still allowed.
+
+### Phase 2
+
+<% impl_status dart: '1.52.1', libsass: false, ruby: false %>
+
+Next, we changed the way angle units are handled for hue parameters to match the
+CSS spec. This means that numbers with `grad`, `rad`, or `turn` units will be
+converted to `deg`: `0.5turn` will be converted to `180deg`, `100grad` will be
+converted to `90deg`, and so on.
+
+Because this change is necessary to preserve CSS compatibility, according to the
+[Dart Sass compatibility policy] it was made with only a minor version bump.
+However, it changes as little behavior as possible to ensure that Sass
+interprets all valid CSS according to the CSS spec.
+
+[Dart Sass compatibility policy]: https://github.com/sass/dart-sass#compatibility-policy
+
+### Phase 3
+
+<% impl_status dart: false, libsass: false, ruby: false %>
+
+Finally, in Dart Sass 2.0.0 color functions will throw errors if they're passed
+a hue parameter with a non-angle unit. Unitless hues will still be allowed.
+
+## Saturation and Lightness
+
+When specifying an HSL color's saturation and lightness, CSS only allows `%`
+units. Even unitless numbers aren't allowed (unlike for the hue). Historically,
+Sass has allowed *any* unit, and interpreted it as `%`. You could even write
+`hsl(0, 100px, 50s)` and Sass would return the color `red`.
+
+To fix this issue and bring Sass in line with the CSS spec, we're making changes
+in two phases:
+
+### Phase 1
+
+<% impl_status dart: '1.32.0', libsass: false, ruby: false %>
+
+Currently, Sass just emits a deprecation warning if you pass a number with a
+unit other than `deg` as a hue to any function. Passing a unitless number was
+still allowed.
+
+### Phase 2
+
+<% impl_status dart: false, libsass: false, ruby: false %>
+
+In Dart Sass 2.0.0 color functions will throw errors if they're passed a
+saturation or lightness parameter with no unit or a non-`%` unit.
+
+## Alpha
+
+When specifying a color's alpha value, CSS (as of [Colors Level 4]) allows
+either unitless values between 0 and 1 or `%` values between `0%` and `100%`. In
+most cases Sass follows this behavior, but the functions `color.adjust()` and
+`color.change()` have historically allowed *any* unit, and interpreted it as
+unitless. You could even write `color.change(red, $alpha: 1%)` and Sass would
+return the opaque color `black`.
+
+[Colors Level 4]: https://www.w3.org/TR/css-color-4/#typedef-alpha-value
+
+To fix this issue and bring Sass in line with the CSS spec, we're making changes
+in three phases:
+
+### Phase 1
+
+<% impl_status dart: '1.55.1', libsass: false, ruby: false %>
+
+Currently, Sass just emits a deprecation warning if you pass a number with any
+unit, including `%`, as an alpha value to `color.change()` or `color.adjust()`.
+
+### Phase 2
+
+<% impl_status dart: false, libsass: false, ruby: false %>
+
+Next, we'll change the way `%` units are handled for the alpha argument to
+`color.change()` and `color.adjust()`. Alphas with unit `%` will be divided by
+`100%`, converting them to unitless numbers between 0 and 1.
+
+Because this change is a bug fix that improves consistency with other Sass
+functions, it will be made with only a minor version bump. It will be changed at
+minimum three months after Phase 1 is released, to give users time to adjust
+their code and avoid the bug.
+
+[Dart Sass compatibility policy]: https://github.com/sass/dart-sass#compatibility-policy
+
+### Phase 3
+
+<% impl_status dart: false, libsass: false, ruby: false %>
+
+Finally, in Dart Sass 2.0.0 `color.change()` and `color.adjust()` will throw
+errors if they're passed an alpha parameter with a non-`%` unit. Unitless alphas
+will still be allowed.
+
+## `math.random()`
+
+[The `math.random()` function] has historically ignored units in `$limit` and
+returned a unitless value. For example `math.random(100px)` would drop "px" and
+return a value like `42`.
+
+A future version of Sass will stop ignoring units for the `$limit` argument and
+return a random integer with the same units.
+
+[The `math.random()` function]: ../modules/math#random
+
+<% example(autogen_css: false) do %>
+  // Future Sass, doesn't work yet!
+  @debug math.random(100px); // 42px
+  ===
+  // Future Sass, doesn't work yet!
+  @debug math.random(100px)  // 42px
+<% end %>
+
+### Phase 1
+
+<% impl_status dart: '1.54.5', libsass: false, ruby: false %>
+
+Currently, Sass emits a deprecation warning if you pass a `$limit` with units to
+`math.random()`.
+
+### Phase 2
+
+<% impl_status dart: false, libsass: false, ruby: false %>
+
+In Dart Sass 2.0.0, passing a `$limit` number with units will be an error.
+
+### Phase 3
+
+<% impl_status dart: false, libsass: false, ruby: false %>
+
+In a minor release after Dart Sass 2.0.0, passing a `$limit` number with units
+to the `math.random()` function will be allowed again. It will return a random
+integer the same units as `$limit`, instead of a unitless number.
+
+## Weight
+
+The [`color.mix()` function] and [`color.invert()` function] have both
+historically ignored units in their `$weight` arguments, despite that argument
+conceptually representing a percentage. A future version of Sass will require
+the unit `%`.
+
+[`color.mix()` function]: ../modules/color#mix
+[`color.invert()` function]: ../modules/color#invert
+
+### Phase 1
+
+<% impl_status dart: '1.55.1', libsass: false, ruby: false %>
+
+Currently, Sass emits a deprecation warning if you pass a `$weight` with no
+units or with units other than `%` to `color.mix()` or `color.invert()`.
+
+### Phase 2
+
+<% impl_status dart: false, libsass: false, ruby: false %>
+
+In Dart Sass 2.0.0, `color.mix()` and `color.invert()` will throw errors if
+they're passed a `$weight` with no unit or a non-`%` unit.
+
+## Index
+
+The [`list.nth()` function] and [`list.set-nth()` function] have both
+historically ignored units in their `$n` arguments. A future version of Sass
+will forbid any units.
+
+[`list.nth()` function]: ../modules/color#nth
+[`list.set-nth()` function]: ../modules/color#set-nth
+
+### Phase 1
+
+<% impl_status dart: '1.55.1', libsass: false, ruby: false %>
+
+Currently, Sass emits a deprecation warning if you pass a `$weight` with no
+units or with units other than `%` to `color.mix()` or `color.invert()`.
+
+### Phase 2
+
+<% impl_status dart: false, libsass: false, ruby: false %>
+
+In Dart Sass 2.0.0, `list.nth()` and `list.set-nth()` will throw errors if
+they're passed an index `$n` with a unit.
diff --git a/source/documentation/breaking-changes/random-with-units.md.erb b/source/documentation/breaking-changes/random-with-units.md.erb
deleted file mode 100644
index 900453e22..000000000
--- a/source/documentation/breaking-changes/random-with-units.md.erb
+++ /dev/null
@@ -1,37 +0,0 @@
----
-title: "Breaking Change: Random With Units"
-introduction: >
-  The `random()` function will no longer ignore units on the `$limit` argument
-  in a future version. Passing a `$limit` with units is deprecated to ensure the
-  compilation results don't change once the new behavior lands.
----
-
-[The `random()` function] has historically ignored units in `$limit` and
-returned a unitless value. For example `random(100px)` would drop "px" and
-return a value like `42`.
-
-A future implementation of Dart Sass will stop ignoring units for the `$limit`
-argument and return a random integer with the same units.
-
-[The `random()` function]: ../modules/math#random
-
-<% example(autogen_css: false) do %>
-  // Future Sass, doesn't work yet!
-  @debug math.random(100px); // 42px
-  ===
-  // Future Sass, doesn't work yet!
-  @debug math.random(100px)  // 42px
-<% end %>
-
-## Transition Period
-
-<% impl_status dart: '1.54.5', libsass: false, ruby: false %>
-
-First, the Sass compiler will emit a deprecation warning for previous uses of
-`random()` when the `$limit` argument has units. The warning will suggest a way
-to preserve the existing behavior and another way that emulates the future
-implementation.
-
-In Dart 2.0.0 passing a `$limit` number with units will be an error, and then in
-a future minor release the `random()` function will return a random integer the
-same units as `$limit`.