We are happy to announce the release of OMNeT++ 5.4.1. This release contains last-minute features and improvements, mostly motivated by the upcoming INET 4 release. Highlights are the typename and exists() operators in NED; nan and inf keywords in NED; support for logarithmic units like dB, dBW, dBm, dBV, dBmV. Qtenv has also gained much more powerful just-in-time debugging capabilities than before.