It won't be released as a fully revised class, only maybe as a set of alternative class features
Rules designer Jeremy Crawford originally indicated in an August 2017 tweet that the UA revised ranger would require revisions before being published:
Before the revised ranger becomes official, it needs further refinement. After that, we'll get it into your hands!
Crawford later clarified in an unofficial Twitter exchange in October 2017:
In the end, there will be 1 ranger: the PH ranger. It will get alternative features. The official game won't have 2 versions of a class
Twitter user: So a published version of the UA Ranger will be published as an 'alternate rule' for the Ranger?
You'll be able to take feature X in place of feature Y. It won't be a whole different class.
However, Jeremy Crawford did eventually make it clear in this July 2018 Twitter exchange that any work on the UA revised ranger as a wholesale revision of the class was no longer occurring, and that at best it was a "possibility" that some alternative class features for the ranger would be released:
Regarding the revised ranger, I mentioned back in 2017 that we have no plans to release an alternative version of a class. That plan hasn’t changed. There is one ranger: the one in the Player’s Handbook.
Twitter user: Are you still considering alternate versions of some of the class and Beast Master features, like you mentioned in the 11/27/2017 Dragon Talk episode?
Alternate features for multiple classes are still a possibility, but we want to do more research before we invest time in them. We don’t want our design to chase phantoms but real desires held by a large number of players.
In short: the revised ranger won't be published as a whole separate class. At most, it'll be a set of alternate class features, allowing players to swap out a particular PHB ranger feature for an alternate one - but the designers plan to do more research before they actually decide to do that.
As of November 2019, this is being playtested in UA
On November 4, 2019, Wizards of the Coast released Unearthed Arcana: Class Feature Variants for playtesting. This UA includes variant class features for every class - including the ranger - that replace or enhance existing features.
As summarized on page 2 of the document, the ranger gains replacements or enhancements for nearly all of its base class features from 1st to 3rd level, as well as a replacement for its 10th-level feature, and an enhancement of one of the Beast Master ranger archetype's features:
The 1st-level Natural Explorer feature (gives benefits from
chosen favored terrain), as well as its 6th- and 10th-level
improvements (choose additional favored terrains), are replaced with
the Deft Explorer feature, a series of 3 benefits that you can choose
one of at each of those same 3 levels, in any order:
- Canny: gain proficiency and expertise in a skill, and 2 language
- Roving: gain 5 feet to walking speed, and gain climbing and swimming
speeds equal to walking speed
- Tireless: give yourself (1d10 + Wis mod) temp HP a number of times
equal to Wis mod, and reduce exhaustion by 1 on short rest
The 1st-level Favored Enemy feature, as well as its 6th- and
14th-level improvements (choose additional favored enemy types), are
all replaced with the Favored Foe feature (learn hunter's mark
without counting against your number of known spells, and cast it
without expending a spell slot or requiring concentration, a number
of times equal to Wis mod).
Rangers alone gain the 2nd-level Fighting Style option Druidic
Warrior (learn 2 druid cantrips that count as ranger spells for you,
and you can swap them on level-up), in addition to the new Fighting
Style options added by the UA for all classes with the feature.
The UA adds a few spells to the ranger spell list (a few, like
entangle and dominate beast, seem like they should already have
been on it).
The 2nd-level Spellcasting feature gains 2 other enhancements.
Spell Versatility (which several other "known" spellcasters get in
the same UA) lets them swap one known spell for a new one of the same
level on a long rest. Spellcasting Focus, obviously, lets them use a
druidic focus in place of material components.
The 3rd-level Primeval Awareness feature (waste a spell slot to
find out that an unknown number of a known type of creature is at an
unknown location within 1 mile, or 6 miles in favored terrain) is
replaced by Primal Awareness (learn 1-2 specified spells at 3rd, 5th,
9th, 14th, and 17th ranger level, and cast each of them once per long
rest without expending a spell slot).
The 10th-level Hide in Plain Sight feature (spend a minute to
camouflage yourself and then press yourself against a surface to get
a +10 to Stealth checks until you move/take an action) is replaced by
the much simpler Fade Away feature (use a bonus action to turn
invisible until the start of your next turn, once per short or long
Finally, the Beast Master ranger gains 2 additional options for
their 3rd-level Ranger's Companion feature: "a primal beast
known as a Beast of the Air or a Beast of the Earth". Their
statblocks are too long to summarize here.
Feedback surveys have already gone out for this UA. It remains to be seen whether some or all of this content will end up being published (and how it will be changed if it is published), but this does seem to reflect what Crawford meant in earlier statements by "alternate class features".