RouterOS v4 released

The new RouterOS version is available on the
download page. Please remember some important
basics before upgrading:
1. Update the Bootloader if using a RouterBOARD
2. If already running RouterOS v3.25 or newer, Update your RouterOS license
3. If you will use Netinstall for installation, make sure you have the latest version of Netinstall
If you are currently running an older version of RouterOS, where license can’t be upgraded to the new format, you can still upgrade, but absolutely
make sure that:
* After successful upgrade click on the “Update License” button in Winbox and make sure the new license is accepted. You will have 72 hours to do this, but it’s recommended to do this immediatelly

http://www.mikrotik.com/download.html