Its not unusual for players to leave the server then come back when its updated, it was like this before for 1.7-1.8.
1.10 update is this so far: Eq and Creative are updated to 1.10 the survival server is due to be updated soon, when? i do not know.
a plugin needs to be rewritten and its a long process.
The server is active you probably have joined at the wrong time zone (around the time australians are awake i think)
but yeah the server is active at times, when the server updates there will be advertising etc so the player count will skyrocket (hopefully lol)
A reletively new thing is Discord chat for the server, staff can be contacted 24/7 here aswell as chatting, roleplaying, voice chat, sharing media and much more:
https://discord.gg/JhhRcPA