Firstly, no idea where of what the Hardware version is so entered V7 as app told me everything was up to date!

I recently purchased 2 plug which installed and work perfectly, so decided to try and add bulbs.   Bought 4 L510B.   Unable to pair any of them, first thought is the 'B' as this is not shown on the app.   i phone/device cannot find each other even when right next to each other!   The plugs are in the same room so no wi fi problems and app has access to local network.   Have tried hard reset of app and bulb (switching on and off 10 times quickly) nothing seems to work, others have tried too and nothing works, so really am suspicious of the (B) not showing on my app being the reason for this.    Any further suggestions would be helpful.