NPD analyst Richard Shim said:
We see two refreshes coming. One in the second half of this year, then one in Q1 [first quarter] of 2014. The Q1  device will have a Retina display plus an updated processor.It sounds similar to the iPad 3 / iPad 4 saga. Apple released the iPad 3 in March of last year, but then followed it up with a moderately tweaked iPad 4 in mid-September.
The iPad 4 upgraded only a few hardware components, such as the processor (an A6X instead of an A5X) and a Lightning connector, which some saw as less of an upgrade and more as a hassle.
Shim added, however, that the date of the Retina iPad mini refresh, which would be the device's third generation, is "still in flux."
Still to be determined, though, is which display technology will be used in the iPad mini 3. One of the possibilities, it's said, is LTPS, or low-temperature polysilicon, which is the same display technology used in the iPhone 5.