The videos on youtube are hidden in my country, and the iqyi subscription is also very expensive here. Until We Meet Again is on Viki, so I think it's possible this one also gets added to the catalogue as well. Anyone has any information on this?

Since UWMA is, I suspect so, yes. Especially with how popular Boun and Prem are.

There is a (2) part  trick to getting the Dramas YOU want to see on Viki and that is you have to use the VIKI TITLE REQUEST FORM  (You can find it on the Site under the  Help Center) to ASK VIKI to create a Channel FOR the Dramas YOU want to see. Then for the 2nd Part you and any OTHER fan wanting to see THAT Drama ON VIKI has to continue to use the VIKI TITLE REQUEST FORM to let Viki KNOW what REGION you live in because whether you are a FREE VIEWER or a PASS HOLDER at VIKI if a particular Drama is NOT Regionally Licensed for the REGION YOU LIVE IN then you CAN NOT WATCH whether you have a PASS or NOT.  

I always tell my Fellow Fans at VIKI to: 

1)Bookmark the VIKI TITLE REQUEST FORM

2) SHARE the FORM with their Friends in their Country/Region so that they can help get the Drama Regionally Licensed so that they WILL be ABLE to WATCH.

3) USE IT!!!

Keep in mind neither a Channel FOR a Drama or a Regional License for one will happen as soon as you send the form in the Drama has to be requested by enough people for it to be worthwhile for Viki to pay the License Fee that went up from $800,000.00 per Drama to the now $1,000,000.00 Fee which is why Viki's Rival Drama Fever had to close they could not afford the Fee increase.  The Regional Licenses do not last FOREVER either, once a Drama receives it. So, you may be able to watch when it is first Licensed, but once it expires you will get the "Not available to you" message even though you may have been halfway through the drama when it expired.  The great thing is though, all you have to do is use the VIKI TITLE REQUEST FORM again to ask them to RENEW the License.  I know for a Fact that Nirvana in Fire has had it's License RENEWED at least (4) times because its FANS diligently used the VIKI TITLE REQUEST FORM again to ask them to RENEW the License. It took a couple of months, but they DID get it licensed AGAIN every time it expired.

Also the Entertainment Business is just that a BUSINESS and it runs on Contracts so the SOONER you request a Channel for a Drama the sooner VIKI can begin negotiating a CONTRACT for that Drama and will hopefully beat the other Streaming sites so that they can get the Drama aired on their site BEFORE anyone else gets one ... so we get to see it sooner.  IF not, don't despair Viki can always get a Late License for a Drama when another Site's "Exclusive" On-Air Contract expires, like they did for Big Dragon after iQiYi's Exclusive expired ... but we have to use the FORM to let them know we want to see a particular Drama and again to get it Regionally licensed for WHERE WE LIVE so we can see it. As long as we do that Viki will keep trying to get the Dramas and the Regional Licenses we NEED.  They may have to wait until another site that got their license first expires, but they WILL keep TRYING to get the Dramas we love.