I was able to vote with v.22 (both local and server side). As I understand - v.23 is only needed for additional ability to see voting results (+ some non-voting additional functions).
My ideas about "so many people haven't voted yet":
1. Some people want to feel like "the only decision maker" - to vote in last moment - so even with small amount of their MNs "determine the whole result by themselves".
2. Many people just didn't understand all details about this proposition and following corrections (For example - foreigners. For example - for me explanation was too complicated and I can' get it 100% clear. But I voted anyway because I think we have to start with something now. Another type of people will act only when they understand 100% easy and clear). So they may decided to wait until further simplistic explanations.
3. Big MN OPs think the have voted, but some percentage of their votes have reset to ABSTAIN (for example due to MN go offline for more than 1 hour). And it is not any easy way for them to check this out.
4. Some Big MN OPs may decided not to vote to mention in a future that "decision got >50% EVEN WITHOUT their involvement!".
5. Some MN OP are "sleeping"... May be we need a mandatory update to wake them up?