OMG they've switched hardware and firmware yet again!?!
This is the fifth time - and that doesn't even count more minor hardware changes! Original HW-150s had a 7816 SoC and Samsung demodulator, like your old one. 2nd-generation boxes had a 7816 but an MStar 1237 demodulator (Samsung quit making the demod used in the original boxes); firmware versions were V1 and V18
. 3rd-gen boxes replaced the 7816 with a 7802; the firmware versions were V2.0 or V2.1. (I have one of those.) 4th-generation went back to the 7816, and the firmware version changed to V4.0 or V4.1. (They had to skip V3 because that was an old firmware version for the original box!)
And it sounds like your new box is a 5th-generation, which has gone back to the 7802 again! And the firmware is now at V5.0. I believe recordings made by 7816 boxes are incompatible with those made by 7802 boxes, but I haven't been able to positively confirm that (although it seems to be true in your case).
iView sells a similar box, and has also changed from a 7816 to a 7802 SoC recently. But they badly screwed up their firmware in the process. Mediasonic seems to do a better job with their firmware - but they did manage to lose the DD5.1 fix they had in V14, didn't they?
As far as closed captions work, a pattern has emerged: CCs work on all HomeWorxes during live viewing; they work on 7816 boxes when time-shifting, but not when playing back recordings (pressing the CC button just displays "invalid"); while on 7802 boxes, they work during playback, but not when time-shifting! Mediasonic has claimed to one of us (DoctorM) that they're working on getting CCs working during time-shifting on 7802 boxes, which should result in them working
in all cases on those boxes
. I'm sure he'd be interested to learn whether Mediasonic made any progress on CCs in V5.0.