Merge pull request #532 from MikeyMJCO/patch-1

Update docs to reflect semver changes.

docs/extensions/info-xml.md

@@ -42,6 +42,7 @@ Here is an example of a full `info.xml` file from [CiviVolunteer](https://github
 
 | CiviCRM Version | Description |
 | -- | -- |
+| 5.0.0 | [`<ver>`](#ver) tags now imply forward compatibility. (e.g. an extension declaring `<ver>5.1</ver>` is displayed on 5.2, 5.3 etc. but *not* on 5.0.) Because 4.7.x and 5.x are substantively the same series, `<ver>4.7</ver>` implies forward compatiblity with 5.x. |
 | 4.7.27 | Added [`<requires>`](#requires) and [`<ext>`](#ext) | 
 | 4.5 | [`<develStage>`](#develStage) is not always required; when using civicrm.org's automated release management, this value is inferred from the version; for manual or private releases, the field should still be defined.
 | 4.2 | Most extensions should be packaged as generic *module* rather than type-specific extensions.
@@ -313,13 +314,20 @@ Elements acceptable within `<urls>`
 ### `<ver>` {:#ver}
 
 * Containing element: [`<compatibility>`](#compatibility)
-* Description: a version of CiviCRM with which this extension is compatible
+* Description: a version of CiviCRM with which this extension is compatible; expressed as two digits
 * Contains: text
 * Example: `4.7`
 
-!!! note
+!!! note "Point releases"
     It is not currently possible to specify compatibility with point releases. If your extension is compatible with CiviCRM 4.7.21 but *not* 4.7.20, then you will need to clearly specify this in the [comments](#comments).
 
+!!! note "Forward compatibility (4.7/5.x)"
+    For CiviCRM 3.x and 4.x, `<ver>` tags must explicitly list all compatible versions.
+
+    For CiviCRM 4.7.x and 5.x, `<ver>` tags imply forward compatibility.
+
+    Because 4.7.x and 5.x are substantively the same series, `<ver>4.7</ver>` implies forward compatiblity with 5.x.
+
 ### `<version>` {:#version}
 
 * Containing element: [`<extension>`](#extension)