On September 29, 2016, AH-Software tweeted that a VOICEROID+EX voicebank for Tohoku Kiritan and a VOCALOID4 update for Tohoku Zunko would be releasing on October 27 that year. The VOCALOID4 update for Zunko would only be a Natural voicebank, much like the SF-A2 miki V4 and the Kaai Yuki V4 packages before her. In addition, her voicebank would be available on its own or as a bundle with the VOCALOID4 software.
A trial version of Zunko's VOCALOID4 voicebank was made available on October 14.
From Ver.4.3.0 of the Vocaloid engine onwards, a XSY group "AHS" was added to Vocaloid. All vocals within the "AHS" group can XSY with each other. This vocal release is part of this group. If a User owns one or more vocal releases within the "AHS" group, XSY between them will open up.
The "AHS" is currently the second largest XSY group within Vocaloid. In total if user was to own every VOCALOID3 and VOCALOID4 Ah software vocal within the "AHS" group, this offers the equivalent of 156 additional voicebanks achievable via XSY. The total tone variation offered by the combined packages comes to a theoretical 169 voicebanks in total.
Note that also "GWL" does not become viable for use with any V3 vocals used as the primarily vocal. This should be considered when using any vocal for XSY within the "AHS" group from V3.
Also note that the updated vocals that brought a Vocaloid from VOCALOID3 into VOCALOID4 provided few differences, aside from adding GWL. Therefore these updates can provide little difference when used for XSY.