Quick update -- I've since learned from other forum posts that this particular model (TB-8704V, which is the Verizon 4G model) did not get updated past 7.1.1, unlike the regular Tab 4 8, which got 8.1. Presumably this is because of Verizon (boo!).
@v1ru5879, another update -- DO NOT GET THE LENOVO TAB 4 8 PLUS being sold by Woot.com! I discovered after receiving it today that there's a well-described bug that causes wi-fi connection to be dropped frequently. There's a long support thread about it here: https://forums.lenovo.com/t5/Lenovo...and/WiFi-issue-with-Tab-4-8-Plus/td-p/3986227 (wish I had seen that before I had ordered it!) No solutions offered by Lenovo. It sounds like it might be a glitch introduced by a system update which they never bothered to patch. Interestingly, this never happens on my Lenovo Tab 4 8 (the non-Plus version). I'm going to start the return process tonight. Sorry if I led you astray!:'(