I receive daily "price buster" emails from many of the major online retailers, and over the past couple of weeks, the retail package of VS Pro X4 has been offered at limited-time price points between US$30 and US$43, so it seems that Corel is flushing excess inventory of that product for some reason.
However, I'll bet this promotion is intended to make room for VS Pro X4 Ultimate and does not necessarily indicate the next major revision (i.e. VS Pro X5) is imminent.
Time WILL tell!
VSX6 Ult 22.214.171.124, CPU i7-860 Lynnfield, 8GB Corsair 1600 DDR3, NVidia GeForce GT240 1GB Video, Samsung 1TB HD, Win7Pro 64bit, MSI P55-GD85 Mobo, LITE-ON IHAS-324-98 R SATA 24X DVD Burner, Hanns-G HH-281HPB 27.5"LCD Mon, OCZ 700W PSU, DirectX 11.0