Iulian reports:

We just noticed a small problem with the 2.9.3 version number in compiler.properties. We use this number to version our bundles we ship with the IDE, and right now it's exactly the same number as for the latest RC. When people upgrade, the RC will be kept instead (Eclipse thinks it needs not re-download the jar, since it has the same version number). Users will see 2.9.3-RC2 as their Scala library instead of 2.9.3.

I had a look at the ant build file, and it should handle this. Could it be that you forgot to pass -Dbuild.release=true on the command line when building the release? Here are the compiler.properties files for 2.9.3 and 2.10.0:

#Thu, 20 Dec 2012 03:40:25 +0100

version.number=2.10.0
maven.version.number=2.10.0
osgi.version.number=2.10.0.v20121205-112020-VFINAL-18481cef9b
copyright.string=Copyright 2002-2012, LAMP/EPFL

#Tue, 26 Feb 2013 03:33:40 +0100

version.number=2.9.3
maven.version.number=2.9.3
osgi.version.number=2.9.3.v20130127-223635-f7b5b312ca
copyright.string=Copyright 2002-2011, LAMP/EPFL

Notice the missing -VFINAL suffix (in the build file, it's called osgi.version.suffix, and it seems to be correctly set when ${build.release} is true).

According to build.number:

• Note: To build a release run ant with -Dbuild.release=true

To build an RC, run ant with -Dmaven.version.suffix=-RCN

Maybe it's less error-prone if -Dbuild.release is scrapped, and replaced by -Dmaven.version.suffix="" (assuming that's what happened)?