Merge pull request #197 from Logofile/sync

Documentation change

Author: Logofile

content/programming-guides/proto2.md

@@ -252,13 +252,18 @@ message SearchRequest {
 
 Deleting fields can cause serious problems if not done properly.
 
-**Do not delete** `required` fields. This is almost impossible to do safely.
-
-When you no longer need a field and all references have been deleted from client
-code, you may delete the field definition from the message. However, you
-**must** [reserve the deleted field number](#fieldreserved). If you do not
-reserve the field number, it is possible for a developer to reuse that number in
-the future.
+**Do not delete** `required` fields. This is almost impossible to do safely. If
+you must delete a `required` field, you should first mark the field `optional`
+and `deprecated` and ensure that all systems which in any way observe the
+message have been deployed with the new schema. Then you can consider removing
+the field (but note that this is still an error-prone process).
+
+When you no longer need a field that is not `required`, first delete all
+references to the field from client code, and then delete the field definition
+from the message. However, you **must**
+[reserve the deleted field number](#fieldreserved). If you do not reserve the
+field number, it is possible for a developer to reuse that number in the future
+and cause a breakage.
 
 You should also reserve the field name to allow JSON and TextFormat encodings of
 your message to continue to parse.

content/reference/rust/index.md renamed to content/reference/rust/_index.md

@@ -464,6 +464,12 @@ described in
 For specific versions supported, see
 [Foundational Java Support Matrix](https://github.com/google/oss-policies-info/blob/main/foundational-java-support-matrix.md).
 
+On Android, Protobuf supports the minimum SDK version that is supported by
+[Google Play services](https://developers.google.com/android/guides/setup) and
+is the default in
+[Jetpack](https://android.googlesource.com/platform/frameworks/support/+/refs/heads/androidx-main/docs/api_guidelines/modules.md#module-minsdkversion).
+If both versions differ, the lower version is supported.
+
 ## Objective-C {#objc}
 
 The protoc version can be inferred from the Protobuf Objective-C minor version