First, please check if the release you are looking for is stored in the Maven repository available at:
If it is an older release and you did not find it within the link above, then you might be able to get it using the following pattern:
Generally all SNMP4J versions can be downloaded by using the following URL pattern:
<version> is the version of the product which can be copied from the CHANGE LOG, for example 1.9.3d.
For SNMP4J-Agent the URL pattern is: