That’s incorrect. Almost all of the acoustic instruments from Hypersonic 2 are included with Halion Sonic in higher quality, with more samples across the keyboard, much more velocity layers and several articulations. Some of the worst sounds were replaced with samples from the Yamaha Motif XF.
The old Hypersonic strings are included in higher quality with the current version of Halion Symphonic Orchestra, which is part of Absolute 3.
A Hypersonic 2 license is included with Halion 6 and Absolute VST Collection 3. In Halion 6’s case, you’ll have to contact support and request a Halion 5 add-on license, which will allow you to use Hypersonic. (2023 update: this is no longer available.)