According to Hunter Gordon, who is another Traveller licensee, it's going to be based in MWM's Traveller 5th (T5).
Which, given what MWM was pushing for playtest on Hunter's site, TravellerRPG.com, is essentially T4.2 ...
The playtest materials are quite, uhm, controversial amongst Traveller fans. Just about EVERYONE who has worked with them has had something to hate in it. Quite honestly, Marc Miller should probably take his hands OFF the rules, and stick to setting. He's generally out of touch with the fan base, and with current trends in both games theory and game design, not to mention the history of what has failed. He also flat out ignores playtesters; relying upon others to filter the playtest results for him, and ignoring even broadly held views.
By the by, everything Marc has released to this point shows a T4 basis, not a CT basis.
The worst element seen is the task system. THe use of a variable number of dice versus stat+skill was problematic in T4, and is likely to be equally unpopular in T5 and Mongoose Traveller. (It was almost unplayable in T4.0, the 4.1 revision did little to make it easier, doesn't handle well (or at all )a number of issues the MegaTraveller, TNE, and DGP-CT task systems handled quite easily and well. The T5 drafts seen so far are better worded versions of the T4.1 task system... but it's functionally the same system, with no significant changes. Of course, the last draft released for comment was over a year ago.
I hope Mongoose has the freedom to reject certain elements of T5. If they don't, a long and bumpy ride is ahead.
And it's a sad thing that SQ gets sidelined.