If the pattern is to be followed, we’re due for another Star Wars box set this 2018. Since 1990, every 7 years a new Star Wars box set gets released. Make my day Disney
They’re going to have to steer clear of the home release windows for TLJ and Solo so as not to compete with themselves, which leaves two (possibly three) choices within the next couple years:
They could put it out at the end of next year, like Nov/Dec time, since Solo will probably hit video in Sept/Oct.
Spring of ‘19, like March or April, is another possibility. There won’t be a new movie hitting home video around that time, and it would sort of be like how the OT dvd hit shelves roughly eight months before “the last Star Wars saga movie ever.”
They could wait until September 2019, closer to Ep9’s theatrical release, but I’m assuming there will be yet another “Force Friday” merchandising blitz that same month and they’d probably want to save it for another time.