diff --git a/app/templates/index.hbs b/app/templates/index.hbs
index 8fae1eb8..aa1cea41 100644
--- a/app/templates/index.hbs
+++ b/app/templates/index.hbs
@@ -98,6 +98,12 @@
             @models={{array 'ember-data' 'v4.x'}}
           >v4.x</LinkTo>
         </li>
+        <li class='list-unstyled' data-test-ember-data-5-link>
+          <LinkTo
+            @route='show'
+            @models={{array 'ember-data' 'v5.x'}}
+          >v5.x</LinkTo>
+        </li>
       </ul>
     </li>
   </ul>
diff --git a/content/ember-data/v5/ember-data-deprecate-legacy-imports.md b/content/ember-data/v5/ember-data-deprecate-legacy-imports.md
new file mode 100644
index 00000000..e65d576b
--- /dev/null
+++ b/content/ember-data/v5/ember-data-deprecate-legacy-imports.md
@@ -0,0 +1,12 @@
+---
+title: Legacy Imports
+until: '6.0'
+since: '5.3'
+displayId: ember-data:deprecate-legacy-imports
+---
+
+Deprecates importing from `ember-data/*` instead of `@ember-data/*` in order to prepare for the eventual removal of the legacy `ember-data/*`
+
+All imports from `ember-data/*` should be updated to `@ember-data/*` except for `ember-data/store`. When you are using `ember-data` (as opposed to installing the individual packages) you should import from `ember-data/store` instead of `@ember-data/store` in order to receive the appropriate configuration of defaults.
+
+<!-- TODO: gather list of imports that need to be updated -->
diff --git a/content/ember-data/v5/ember-data-deprecate-non-strict-id.md b/content/ember-data/v5/ember-data-deprecate-non-strict-id.md
new file mode 100644
index 00000000..3dac07ee
--- /dev/null
+++ b/content/ember-data/v5/ember-data-deprecate-non-strict-id.md
@@ -0,0 +1,16 @@
+---
+title: Non Strict Id
+until: '6.0'
+since: '5.3'
+displayId: ember-data:deprecate-non-strict-id
+---
+
+Currently, EmberData expects that the `id` property associated with a resource is a string.
+
+However, for legacy support in many locations we would accept a number which would then immediately be coerced into a string.
+
+We are deprecating this legacy support for numeric IDs.
+
+The goal is that in the future, you will be able to use any ID format so long as everywhere you refer to the ID you use the same format.
+
+However, for identifiers we will always use string IDs and so any custom identifier configuration should provide a string ID.
diff --git a/content/ember-data/v5/ember-data-deprecate-non-strict-types.md b/content/ember-data/v5/ember-data-deprecate-non-strict-types.md
new file mode 100644
index 00000000..92918253
--- /dev/null
+++ b/content/ember-data/v5/ember-data-deprecate-non-strict-types.md
@@ -0,0 +1,22 @@
+---
+title: Non Strict Types
+until: '6.0'
+since: '5.3'
+displayId: ember-data:deprecate-non-strict-types
+---
+
+Currently, EmberData expects that the `type` property associated with a resource follows several conventions.
+
+- The `type` property must be a non-empty string
+- The `type` property must be singular
+- The `type` property must be dasherized
+
+We are deprecating support for types that do not match this pattern in order to unlock future improvements in which we can support `type` being any string of your choosing.
+
+The goal is that in the future, you will be able to use any string so long as it matches what your configured cache, identifier generation, and schemas expect.
+
+E.G. It will matter not that your string is in a specific format like singular, dasherized, etc. so long as everywhere you refer to the type you use the same string.
+
+If using @ember-data/model, there will always be a restriction that the `type` must match the path on disk where the model is defined.
+
+e.g. `app/models/foo/bar-bem.js` must have a type of `foo/bar-bem`
diff --git a/content/ember-data/v5/ember-data-deprecate-non-uniq-collected-payloads.md b/content/ember-data/v5/ember-data-deprecate-non-uniq-collected-payloads.md
new file mode 100644
index 00000000..f551817d
--- /dev/null
+++ b/content/ember-data/v5/ember-data-deprecate-non-uniq-collected-payloads.md
@@ -0,0 +1,31 @@
+---
+title: Non Uniq Collection Payloads
+until: '6.0'
+since: '5.3'
+displayId: ember-data:deprecate-non-unique-collection-payloads
+---
+
+Deprecates when the data for a `hasMany` relationship contains duplicate identifiers.
+
+Previously, relationships would silently de-dupe the data when received, but this behavior is being removed in favor of erroring if the same related record is included multiple times.
+
+For instance, in JSON:API the below relationship data would be considered invalid:
+
+```json
+{
+ "data": {
+  "type": "article",
+   "id": "1",
+   "relationships": {
+     "comments": {
+       "data": [
+         { "type": "comment", "id": "1" },
+         { "type": "comment", "id": "2" },
+         { "type": "comment", "id": "1" } // duplicate
+       ]
+    }
+ }
+}
+```
+
+To resolve this deprecation, either update your server to not include duplicate data, or implement normalization logic in either a request handler or serializer which removes duplicate data from relationship payloads.
diff --git a/content/ember-data/v5/ember-data-deprecate-relationship-remote-update-clearing-local-state.md b/content/ember-data/v5/ember-data-deprecate-relationship-remote-update-clearing-local-state.md
new file mode 100644
index 00000000..f3b29f4b
--- /dev/null
+++ b/content/ember-data/v5/ember-data-deprecate-relationship-remote-update-clearing-local-state.md
@@ -0,0 +1,105 @@
+---
+title: Relationship Remote update clearing Local state
+until: '6.0'
+since: '5.3'
+displayId: ember-data:deprecate-relationship-remote-update-clearing-local-state
+---
+
+Deprecates when a relationship is updated remotely and the local state is cleared of all changes except for "new" records.
+
+Instead, any records not present in the new payload will be considered "removed" while any records present in the new payload will be considered "added".
+
+This allows us to "commit" local additions and removals, preserving any additions or removals that are not yet reflected in the remote state.
+
+For instance, given the following initial state:
+
+```plaintext
+remote: A, B, C
+local: add D, E
+       remove B, C
+=> A, D, E
+```
+
+If after an update, the remote state is now A, B, D, F then the new state will be
+
+```plaintext
+remote: A, B, D, F
+local: add E
+       remove B
+=> A, D, E, F
+```
+
+Under the old behavior the updated local state would instead have been
+
+```plaintext
+=> A, B, D, F
+```
+
+Similarly, if a belongsTo remote State was A while its local state was B, then under the old behavior if the remote state changed to C, the local state would be updated to C. Under the new behavior, the local state would remain B.
+
+If the remote state was A while its local state was `null`, then under the old behavior if the remote state changed to C, the local state would be updated to C.  Under the new behavior, the local state would remain `null`.
+
+Thus the new correct mental model is that the state of the relationship at any point in time is whatever the most recent remote state is, plus any local additions or removals you have made that have not yet been reflected by the remote state.
+
+> Note: The old behavior extended to modifying the inverse of a relationship. So if you had local state not reflected in the new remote state, inverses would be notified and their state reverted as well when "resetting" the relationship.  Under the new behavior, since the local state is preserved the inverses will also not be reverted.
+
+### Resolving this deprecation
+
+Resolving this deprecation can be done individually for each relationship or globally for all relationships.
+
+To resolve it globally, set the `DEPRECATE_RELATIONSHIP_REMOTE_UPDATE_CLEARING_LOCAL_STATE` to `false` in ember-cli-build.js
+
+```js
+let app = new EmberApp(defaults, {
+  emberData: {
+    deprecations: {
+       // set to false to strip the deprecated code (thereby opting into the new behavior)
+      DEPRECATE_RELATIONSHIP_REMOTE_UPDATE_CLEARING_LOCAL_STATE: false
+    }
+  }
+})
+```
+
+To resolve this deprecation on an individual relationship, adjust the `options` passed to the relationship. For relationships with inverses, both sides MUST be migrated to the new behavior at the same time.
+
+```js
+class Person extends Model {
+ @hasMany('person', {
+   async: false,
+   inverse: null,
+   resetOnRemoteUpdate: false
+ }) children;
+
+ @belongsTo('person', {
+   async: false,
+   inverse: null,
+   resetOnRemoteUpdate: false
+ }) parent;
+}
+```
+
+> Note: false is the only valid value here, all other values (including missing) will be treated as true, where `true` is the legacy behavior that is now deprecated.
+
+Once you have migrated all relationships, you can remove the the resetOnRemoteUpdate option and set the deprecation flag to false in ember-cli-build.
+
+### What if I don't want the new behavior?
+
+EmberData's philosophy is to not make assumptions about your application. Where possible we seek out "100%" solutions – solutions that work for all use cases - and where that is not possible we default to "90%" solutions – solutions that work for the vast majority of use cases. In the case of "90%" solutions we look for primitives that allow you to resolve the 10% case in your application. If no such primitives exist, we provide an escape hatch that ensures you can build the behavior you need without adopting the cost of the default solution.
+
+In this case, the old behavior was a "40%" solution. The inability for an application developer to determine what changes were made locally, and thus what changes should be preserved, made it impossible to build certain features easily, or in some cases at all. The proliferation of feature requests, bug reports (from folks surprised by the prior behavior) and addon attempts in this space are all evidence of this.
+
+We believe the new behavior is a "90%" solution. It works for the vast majority of use cases, often without noticeable changes to existing application behavior, and provides primitives that allow you to build the behavior you need for the remaining 10%.
+
+The great news is that this behavior defaults to trusting your API similar to the old behavior.  If your API is correct, you will not need to make any changes to your application to adopt the new behavior.
+
+This means the 10% cases are those where you can't trust your API to provide the correct information. In these cases, because you now have cheap access to a diff of the relationship state, there are a few options that weren't available before:
+
+- you can adjust returned API payloads to contain the expected changes that it doesn't include
+- you can modify local state by adding or removing records on the HasMany record array to remove any local changes that were not returned by the API.
+- you can use `<Cache>.mutate(mutation)` to directly modify the local cache state of the relationship to match the expected state.
+
+What this version (5.3) does not yet provide is a way to directly modify the cache's remote state for the relationship via public APIs other than via the broader action of upserting a response via `<Cache>.put(document)`. However, such an API was sketched in the Cache 2.1 RFC `<Cache>.patch(operation)` and is likely to be added in a future 5.x release of EmberData.
+
+This version (5.3) also does not yet provide a way to directly modify the graph (a general purpose subset of cache behaviors specific to relationships) via public APIs. However, during the 5.x release series we will be working on finalizing the Graph API and making it public.
+
+If none of these options work for you, you can always opt-out more broadly by implementing a custom Cache with the relationship behaviors you need.
diff --git a/ember-cli-build.js b/ember-cli-build.js
index 591b0de6..2e8bd346 100644
--- a/ember-cli-build.js
+++ b/ember-cli-build.js
@@ -33,6 +33,7 @@ module.exports = function (defaults) {
         '/ember-data/v2.x',
         '/ember-data/v3.x',
         '/ember-data/v4.x',
+        '/ember-data/v5.x',
         '/ember-cli/v2.x',
         '/ember-cli/v4.x',
         '/ember-cli/v5.x',
diff --git a/lib/content-docs-generator/index.js b/lib/content-docs-generator/index.js
index cb0fd4ec..017daba1 100644
--- a/lib/content-docs-generator/index.js
+++ b/lib/content-docs-generator/index.js
@@ -14,6 +14,7 @@ const contentFolders = [
   'ember-data/v2',
   'ember-data/v3',
   'ember-data/v4',
+  'ember-data/v5',
   'ember-cli/v2',
   'ember-cli/v4',
   'ember-cli/v5',