WordPress 4.9.7 is a security release that fixes 17 bugs in WordPress, as announced by Aaron Campbell.
The release caused some confusion from a naming perspective, as blog posts had been written scheduling 4.9.7, which are now bumped to 4.9.8 and on the schedule as outlined.
As WordPress begins to formalize the minor release cycle a bit more than years past — give the new major release cycle — it accounts for some stuff that's a bit different, like this slight naming confusion.
The release appears to be a fairly standard security release — time sensitive, like all releases, but nothing crazy (from my point of view).
Joshua Wold and Paul Biron are serving as leads for 4.9.8.