I\'m looking for a logging framework and it seems log4net is or was very popular. The last release was over 2 years ago. It has not been updated for .net 3.0 or 3.5 or even
Log4j (which was the basis for log4net) hasn't been updated in years. There are other alternatives from the same author (slf4j and logback) and others, but log4j is still used plenty and plenty viable. It isn't dead, it just got to the point where there was nothing more really was needed for it. Nothing that justified the work or wouldn't break backwards compatability. When that happens to a commercial project, the company has to invent a whole other purpose for the product or do something else and the product does indeed die. In open source, not really.
As a point of comparison, JUnit was basically going nowhere for years. Then Java got annotations, JUnit got competition (TestNG) and it is suddenly moving along again. Now the original developers may not end up being around in every case, but then the project would be forked or adapted. For example, TestNG allowed a smooth migration path from JUnit.
So the bottom line is if it is popular and used, it will not die on you.