We are happy to announce that OMNeT++ 4.5 is now available for download. The focus of version 4.5 was to improve the usability of the Graphical Runtime Environment (Tkenv). The Tkenv GUI has been redesigned for single-window mode to improve usability and user experience. A new message logging mode was added in the log window that shows the message exchanges in the selected module only. Tkenv has also received a new, modern look and feel, due to the use of the Ttk widgets and a custom Ttk theme.