All it means is that there won’t be upgrades/improvements to ZK, 3.4 will still run. So there’s no need to move to 3.5 independent of upgrading Solr just because that version of ZK is unsupported going forward.
I haven’t personally tried to run 3.5 against an earlier version, but one thing you’ll probably want to do if you try it is whitelist “ruok”, “mntr”, and “conf” in your Zookeeper config, see the Zookeeper documentation. NOTE: that is only necessary if you want to see the Zookeeper status in the admin UI, those commands aren’t used by anything else in Solr. The JIRA (SOLR-8346) contains a _ton_ of changes, but the mostly fall in two categories: Using a file rather than strings in tests and trying to handle the whitelist programmatically, neither of which are relevant to just dropping a newer version of ZK in. Again, though, there’s no reason to even try it unless you need something in a more recent ZK. Best, Erick > On Apr 9, 2020, at 5:28 AM, Bram Van Dam <bram.van...@intix.eu> wrote: > > Hey folks, > > The ZK team just announced that they're dropping 3.4 support as of the > 1st of June, 2020. > > What does this mean for those of us still on Solr < 8.2? From what I can > tell, ZooKeeper 3.5+ does not work with older Solr versions. > > Has anyone managed to get a 3.5+ to work with Solr 7 at all? > > Thanks, > > - Bram
