Tamron Japan just announced that they are going to make a new version of the actual Tamron 70-300mm
According to the dpreview press release “the SP 70-300mm F4-5.6 Di VC USD is the company’s first lens to feature its latest Ultrasonic Silent Drive (USD) autofocus motor, with full-time manual focus override. The optical design includes an element made from Extra-Low Dispersion (XLD) glass“