However, I can say from personal experience that the newer Sticks are much superior to the 3600 (which was vastly superior to the 3500). Should you find a new Stick on sale some time (maybe soon, maybe not until Black Friday) you may want to consider upgrading at a good price at that time.
However, to limit things specifically to your question, yes, that device is supported, as the link above shows.
DBDukes https://www.dbdukes.com/Roku Ultra (4660) Roku Streambar (9102) Roku Streaming Stick+ (3810)
Re: Can you let me know if OS 10 will be rolled out for 3600x model
And to answer your question about when it will roll out, only Roku knows. They stagger their rollouts by geographical area, as well as by device model. It could take a number of weeks before it's offered on every eligible device, and even longer if they encounter a "hiccup" that forces them to pause things. In the past it's usually been 2-3 months before it's available everywhere on every device.
Dan Ultra (4640), Ultra (4670), Ultra (4800), Premiere (3920), Insignia 720p Roku TV, Sharp 4K Roku TV, Nvidia Shield, Windows 10 Pro x64 running Serviio and Plex on a wired Gigabit network.