Proxmox 3.x has implemented a new repository setup. Each time you log into it a dialogue box pops up with the message:
You do not have a valid subscription for this server. Please visit www.proxmox.com to get a list of available options.
One way to remove the message is to purchase a subscription from the Proxmox team. Remember that paying subscriptions keeps the development of Proxmox progressing. For the recent release, the subscription cost has been heavily reduced and is more affordable than ever.
The following procedure is allowed under the License (aGPLv3) used for Proxmox however future updates may break your code and you may have to re-apply it or apply a different change.
NOTE: For Proxmox 4.2 and above you need to edit:
/usr/share/pve-manager/ext6/pvemanagerlib.js
The process consist in edit the file 'pvemanagerlib.js':
# cp /usr/share/pve-manager/ext4/pvemanagerlib.js /usr/share/pve-manager/ext4/pvemanagerlib.js_BKP
# vim /usr/share/pve-manager/ext4/pvemanagerlib.js
Note: You may need to clear your web browser cache after applying this code change.