It has been changes recently in tzdata.
Early Novosibirsk was in the same timezone as Omsk.
But now it is the same timezone as Krasnoyarsk.
In settings I choose "UTC +6 Omsk, Novosibirsk"
(just because I live in Novosibirsk) and in my profile I see
novosibirsk, Russia - 5:28pm local time - 1 hr behind
Actually it is 6:28 pm in my city.
Mon 4 Dec 18:28:59 +07 2017
(my system is Ubuntu 16.04)
google: russia omsk localtime
So you (Upwork) need to fix timezones descriptions.
Additionally: If I choose Krasnoyarsk +7 timezone, in my profile I see:
novosibirsk, Russia - 6:33pm local time - 1 hr behind
I'm so confused. It always says '1 hr behind' no matter weather it shows 5:28 pm or 6:33 pm.
I'm afraid I can miss appointments because of this.
I would not worry too much! I had recently a customer here who said he was from New Zealand, and his profile did show accordingly. However, the timezone pointe to London. In fact in UpWork you can have time zone different from your "location" – which does make a lot of sense.
I recommend asking the customer about timezone, then you can perhaps get it right – at least in a way they want it to be.