Hi Chaplin,
A Bluetooth 4.2 device can communicate with a Bluetooth 4.1 and 4.0 device(back compatible) provided that the 4.2 device does not use any Bluetooth 4.2 features.
In PSoC Creator, you can use BLE component(v3.1 and v3.2) which are Bluetooth 4.2 compatible, i.e they support the 4.2 features.
Say you have a CYBLE-222005-00, which is a 4.1 device. Now, you can still use BLE component v3.1 and v3.2. PSoC Creator knows that CYBLE-222005-00 is a 4.1 device and will return an error(and sometimes will not allow) if you try to use 4.2 features.
However if you want to restrict to Bluetooth 4.1, you will have to use older version of BLE Component, version v2.30. It is not recommended to use a older version because later versions have bug fixes and advanced features. To change version of component, right-click on project, select 'Update Components...', select v2.3 under BLE.
