// 1. Client meldt zich aan
[Client] --(Write version: "5")--> [Server: ClientStatusChar]
[Client] --(Subscribe)------------> [Server: ClientControlChar]
// 2. App checkt status
[App] --(Read ClientStatus)----> [Server]
App denkt: "Client heeft v5, ik heb v6. Update nodig!"
// 3. App start de dans
[App] --(Write: "START_OTA")---> [Server: ClientControlChar]
[Server] --(Notify)---------------> [Client]
// 4. De wissel
Client disconnect van Server -> Start Advertising
App disconnect van Server -> Scant naar Client OTA
// 5. De eigenlijke OTA
[App] --(Direct BLE OTA)-------> [Client (nu in Server mode)]