Connect to nRF peripheral from older MacBook (BLE 4.2) central fails

[TimExto]

We have a peripheral based on s132 soft device.  Older MacBook Pro (BLE 4.2 or 4.0) sees the advertisement and tries to connect, but fails.  This was not in our original target design, so I am guessing the SDK is configured to require BLE 5.0.  Can nRF 52832 with s132 be easily configured to support BLE 4.x?  We do not need the more secure pairing/bonding options offered by BLE 5.0.

[Hung Bui]

Hi Tim, 

By default a BLE 5.0 device is backward compatible with BLE v4.0, at least on basic communication. 
There could be the chance that the device require some advanced features and reject the connect if the peer doesn't support it, for example LE Secure Connection for pairing.

But it's hard to tell without any log or better a sniffer trace.  Could you try capture a sniffer trace when you connect to the device ? If you use Nordic sniffer,  you would need to follow the advertiser before it can follow the connection. 

[TimExto]

Thanks, very helpful.  I bet we have enabled LE Secure Connection and will look for that.  I don't have access to a sniffer but will get some logs if I can't find config problem.  I am only guessing this is a BLE version problem because it has just appeared on 2 older MacBooks.