Bonded clients do not work when switching from 1.4.2 to 2.0.0 or vice versa

[KlausMu]

I am using NimBLE with an ESP32. It seems the way bonded clients are stored in NVS changed from NimBLE 1.4.2 to 2.0.0.

Going from 1.4.2 to 2.0.0
In 2.0.0, I can connect to an already bonded peer (which was bonded in 1.4.2). Even direct advertisement works (see #651)
But when sending data, the result is

D NimBLECharacteristic: >> sendValue
D NimBLECharacteristic: << sendValue: No clients subscribed.
D NimBLECharacteristic: >> sendValue
D NimBLECharacteristic: << sendValue: No clients subscribed.

Normally, in version 1.4.2, when sending data, there is something like

D NimBLECharacteristic: >> setValue: length=8, data=0000510000000000, characteristic UUID=0x2a4d
D NimBLECharacteristic: << setValue
D NimBLECharacteristic: >> notify: length: 8
D NimBLECharacteristicCallbacks: onNotify: default
D NimBLEServer: >> handleGapEvent:
D NimBLECharacteristicCallbacks: onStatus: default
D NimBLECharacteristic: << notify
D NimBLECharacteristic: >> setValue: length=8, data=0000000000000000, characteristic UUID=0x2a4d
D NimBLECharacteristic: << setValue
D NimBLECharacteristic: >> notify: length: 8
D NimBLECharacteristicCallbacks: onNotify: default
D NimBLEServer: >> handleGapEvent:
D NimBLECharacteristicCallbacks: onStatus: default
D NimBLECharacteristic: << notify

As a result, I have to delete all bonds in 2.0.0 and to repair them. From that on, everything works as expected.

Going from 2.0.0 to 1.4.2
When going back from 2.0.0 to 1.4.2, the software crashes at

void NimBLEDevice::init(const std::string &deviceName) {
  ble_store_config_init();

If there was no bonded peer in 2.0.0, going back to 1.4.2 works without problem.

[h2zero]

It appears this may be a result of upstream changes in the way the data is stored in NVS, I haven't identified the changes yet but it may just have to be another part of the breaking changes coming with 2.0.0 release.