this.serverCallback is not a function

[Sturmenstrudel]

Hello,
I saw there were some upgrades on the code, so I reinstalled on my raspberry the latest repository but I am getting now the following error, as soon as an application (Wahoo Systm or RGT) connects via BLE.
Do you know how to fix it? Error message copied below.

Merci
Guido

OnReadRequest : Fitness Machine Feature
[server.js] - Bike is under control
/home/pi/kettlerUSB2BLE/BLE/fitness-control-point-characteristic.js:97
this.serverCallback(this.buildResponse(state, ResultCode.success)); // ok
^

TypeError: this.serverCallback is not a function
at FitnessControlPoint.onWriteRequest (/home/pi/kettlerUSB2BLE/BLE/fitness-control-point-characteristic.js:97:11)
at emitMany (events.js:147:13)
at FitnessControlPoint.emit (events.js:224:7)
at Gatt.handleWriteRequestOrCommand (/home/pi/kettlerUSB2BLE/node_modules/@abandonware/bleno/lib/hci-socket/gatt.js:922:26)
at Gatt.handleRequest (/home/pi/kettlerUSB2BLE/node_modules/@abandonware/bleno/lib/hci-socket/gatt.js:344:23)
at Gatt.onAclStreamData (/home/pi/kettlerUSB2BLE/node_modules/@abandonware/bleno/lib/hci-socket/gatt.js:274:8)
at emitTwo (events.js:131:20)
at AclStream.emit (events.js:214:7)
at AclStream.push (/home/pi/kettlerUSB2BLE/node_modules/@abandonware/bleno/lib/hci-socket/acl-stream.js:26:10)
at BlenoBindings.onAclDataPkt (/home/pi/kettlerUSB2BLE/node_modules/@abandonware/bleno/lib/hci-socket/bindings.js:194:21)