Server list is grey when selecting server

Hi all

I last played Mop in december or so, I came back today (23 march 2016) to find that after logging in, my server list was grey. Is there something I have to manually update ? A new server list perhaps ? Just to be clear, the names of the servers are grey instead of green or red. My friends that I played with a few months ago are also having this problem, so I assume it's not just my PC.

Thanks in advance

Frostwolf has been upgraded to 5.4.8, you are still using old 5.4.2 client.
So now you have 3 different options:
1) go here: https://www.warmane.com/download and get full 5.4.8 client by selecting "Mist of Pandaria"
2) or by selecting "MoP minimal", it is a 16MB installer which let you play and download the game at same time
3) if you are using 5.4.2 WITHOUT WoD models then you can Upgrade it to 5.4.8 by just downloading the "wow.exe" file from 5.4.8 torrent and place it inside your 5.4.2 folder

Thank you very much for the fast reply, I had thought it would be something like this.