The latest patch, 2.15, was released in December 2008. When 2.20 will be out, no one knows. It is still in developement and there was no releasedate given so far.
A common reason for not seing any servers is when BF2 is not up to date, 1.41 is a must have. In the past most people with this problem had 1.4 instead of 1.41 installed.
Another possible reason are wrong filter settings in the ingame browser.
