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Except Legend is the big patch. Big patches will always hit in time for the holidays. Smaller patches to fill the gap in between.
Unless this PvP work is putting localization 3 months behind schedule, there is no way Jump isn't coming out in the next month or two and Legend for Christmas.

You take KMS' release month. Add 6 months. You have our release month. Its worked out that way for a while now.
The only question is whether or not we get Jump as an All-In-One deal like Aftershock. I doubt it.

You may want to check your math there, bub.

While Jump coming out in a month would indeed match the "six month rule", though barely since the first Jump patch came the last day of March, but using that assumption of a constant localization rate would mean that Legend, a patch that first hit the official KMS servers in July, couldn't arrive in GMS any earlier than January of next year.

Personally, I don't see any way GMS will be getting Legend within this year.
Yes, the patch started in July, but KMS just got Demon Slayers three weeks ago.
Someone may prove me wrong here, but I'm pretty sure that GMS getting content four months after KMS got it would be unprecedented.

The real question is what they're going to pad in the rest of the year.
Jump is a significant patch, it's true, but it basically comes down to three parts: skill revamps, Monster Park, and PQ revamp.
They'll likely stick it in one big patch and unlock the next part every week or two (a la Chaos).
Some people have pretended that the PQ revamp presents an issue with this method though it does not; simply deactivate PQs until the update.

Having no PQs for two to four weeks might be theoretically very upsetting, but it won't be nearly as big a deal was having to wait for Monster Park after Jump starts. Keep in mind that Jump also means the removal of Party Play zones, so if it's one big patch, high levels will be SOL until Monster Park comes out.

Still, with one to two weeks between unlocks, that still only comes out to a month's worth of content, making for a rather depressing end up the year.
Compare to last year:
- At the same time last year, we were one week into VPQ right now, so everyone was rather giddy (making me laugh heartily at those under the impression that the start of school means no big patches).
- The end of September brought Hob PQ and Ninja Castle.
- October was dull except for the cool effect rings that no longer give effects.
- November sucked.
- December = Big Bang.

Based on that, I'd put the Jump patch in either December or late September.
I will add that I expect (hope) October to bring the return of Witch Belts since GMS seems keen on subverting any benefits brought on by the Crafting system.