After a series of public beta versions, Access Music released a final build of OS 4.5 which can be downloaded free of charge from the Access Music website. OS4.5 focuses on additional vintage effect emulations and additions to the modulation matrix.
The “Vintage Chorus” was modeled after one of the nicest and most famous choruses build in the late 70s. The flexible subset of parameters allows seamless “morphing” from one emulation to another without having 
to change the algorithm and therefore stop the sound. It’s a great addition to the TI’s sound engine making it really easy to emulate the famous chorus ensemble sound found in many productions back from 70s and 80s.
The “Air Chorus” is based on creating the Chorus effect in the air, right in between the speakers. In difference to many other chorus effects, it works more subtile and opens the stereo panorama up in an more natural and less intrusive way.
OS4.5 also features a rotary speaker emulation which offers the usual controls such as a fast/slow setting in combination with creative controls such as microphone distance as well as a crossover setting which allows you to limit the effect to a certain frequency range.
And there are now modulation matrix sources which allow Virus TI users to add further “analog” feeling to pretty much any parameter available within the over 100 modulation destinations. Access claims, it adds “unsteadiness” and enables covers a wide range of those beloved analog side effects known from slightly damaged or simply poorly engineered vintage synths.
The update can be downloaded free of charge from the Access Music website: www.virus.info