Apple has never supported SPP on the iPad or iPhone. You have to use WiFi for a serial connection (via TELNET). Apple does support BLE (Bluetooth Low Energy), but there is no equivalent there to SPP.
I've been able to use a Roving Network's RN-XV module in an xBee socket (like on the Propeller Activity Board) as a serial console with a iPad running Telnet Lite (from the Apple App Store). You could use the RN-XV module with a 5V adapter (https://www.parallax.com/product/32401) and a BS2 if you adjust the Baud of the RN-XV to something like 1200 Baud. The RN-XV default of 9600 Baud is a little dicey with a BS2.
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If found this support page: https://support.apple.com/en-us/HT204387
Note that Apple doesn't seem to support SPP which is the profile used by the RN-42.
I've been able to use a Roving Network's RN-XV module in an xBee socket (like on the Propeller Activity Board) as a serial console with a iPad running Telnet Lite (from the Apple App Store). You could use the RN-XV module with a 5V adapter (https://www.parallax.com/product/32401) and a BS2 if you adjust the Baud of the RN-XV to something like 1200 Baud. The RN-XV default of 9600 Baud is a little dicey with a BS2.