Update UPGRADING.md

Author: silvanocerza

Diff for: docs/UPGRADING.md

@@ -54,6 +54,16 @@ func InitWithProfile(instance *rpc.Instance, profileName string, sketchPath *pat
 
 The errors are automatically sent to output via `feedback` package, as for the other `Init*` functions.
 
+### `board attach` CLI command changed behaviour
+
+The `board attach` CLI command has changed behaviour: now it just pick whatever port and FQBN is passed as parameter and
+saves it in the `sketch.json` file, without any validity check or board autodetection.
+
+### `cc.arduino.cli.commands.v1.BoardAttach` gRPC interface command removal
+
+The `cc.arduino.cli.commands.v1.BoardAttach` gRPC command have been removed. This feature is no more available throguh
+gRPC.
+
 ## 0.28.0
 
 ### Breaking changes in libraries name handling

Diff for: docs/sketch-specification.md

@@ -71,11 +71,10 @@ the `data` folder, so any non-code files outside the `data` folder are stripped.
 Arduino CLI and Arduino Web Editor use a file named sketch.json, located in the sketch root folder, to store sketch
 metadata.
 
-The `cpu` key contains the board configuration information. This can be set via
-[`arduino-cli board attach`](commands/arduino-cli_board_attach.md) or by selecting a board in the Arduino Web Editor
-while the sketch is open. With this configuration set, it is not necessary to specify the `--fqbn` or `--port` flags to
-the [`arduino-cli compile`](commands/arduino-cli_compile.md) or [`arduino-cli upload`](commands/arduino-cli_upload.md)
-commands when compiling or uploading the sketch.
+The `cpu` key contains the board configuration information. This can be set manually or by selecting a board in the
+Arduino Web Editor while the sketch is open. With this configuration set, it is not necessary to specify the `--fqbn` or
+`--port` flags to the [`arduino-cli compile`](commands/arduino-cli_compile.md) or
+[`arduino-cli upload`](commands/arduino-cli_upload.md) commands when compiling or uploading the sketch.
 
 The `included_libs` key defines the library versions the Arduino Web Editor uses when the sketch is compiled. This is
 Arduino Web Editor specific because all versions of all the Library Manager libraries are pre-installed in Arduino Web

Diff for: mkdocs.yml

@@ -52,7 +52,6 @@ nav:
   - Command reference:
       - arduino-cli: commands/arduino-cli.md
       - board: commands/arduino-cli_board.md
-      - board attach: commands/arduino-cli_board_attach.md
       - board details: commands/arduino-cli_board_details.md
       - board list: commands/arduino-cli_board_list.md
       - board listall: commands/arduino-cli_board_listall.md