Add note to docs that socket v3 is still under development.

docs/src/developers/client/changelog.md

@@ -4,6 +4,8 @@ The websocket on the FacilMap server provides different API versions (implemente
 
 ## v5.0.0 (API v3)
 
+_Note: This socket version is still under development and will still change. Do not use it in production yet._
+
 * “symbol” was renamed to “icon” everywhere. This applies to `Marker.symbol`, `Type.defaultSymbol`, `Type.symbolFixed`, `Type.fields[].controlSymbol` and `Type.fields[].options[].symbol`.
 * “pad” was renamed “map” everywhere. This applies to the `padData` and `deletePad` socket events and `getPad` (including its `padId` request property), the `findPads`, `createPad`, `editPad`, `deletePad`, `setPadId` client/socket methods, the `PadNotFoundError`, and the `Marker.padId`, `Line.padId`, `Type.padId`, `View.padId` and `HistoryEntry.padId` properties.