That error comes from an #error statement in "PostController.m". For iOS the relevant lines are:
#if defined(__IPHONE_OS_VERSION_MIN_REQUIRED) && (__IPHONE_OS_VERSION_MIN_REQUIRED < 50000)
#error If you support iOS prior to 5.0, you must re-enable CFStreamCreateBoundPairCompat.
#endif
Immediately below that is an 'if/else' block of code, where the first line is 'if (NO)'.
That 'if (NO)' is what's disabling use of CFStreamCreateBoundPairCompat.
You should replace those 'if/else' lines with '#if/#else/#endif' to compile either the first or second block of code depending on which iOS SDK you're targeting:
#if (__IPHONE_OS_VERSION_MIN_REQUIRED < 50000)
CFStreamCreateBoundPairCompat(
NULL,
((inputStreamPtr != nil) ? &readStream : NULL),
((outputStreamPtr != nil) ? &writeStream : NULL),
(CFIndex) bufferSize
);
#else
CFStreamCreateBoundPair(
NULL,
((inputStreamPtr != nil) ? &readStream : NULL),
((outputStreamPtr != nil) ? &writeStream : NULL),
(CFIndex) bufferSize
);
#endif