The BlazePod system relies on the BLE (Bluetooth Low Energy) standard which supports more than 20 simultaneous connections.
Almost all Apple devices are fully compliant with this standard, but Android phone manufacturers vary. For some Android devices, it takes time to add the supportability for more simultaneous connections. Most Android phones can connect to 12 pods, assuming the software version is up to date.
In the past 2 years, the maximum number of simultaneous connections has increased by Android phone manufacturers, so it’s a matter of time until all phones will have this support.