Vocaloids that Should Get a V4 Japanese Update

Some people wish some Vocaloids get a V4 Japanese update. Tell me who should be updated.
The Top Ten
1 IA (Vocaloid) IA is a humanoid persona voiced by a singing synthesizer application developed by 1st Place Co., Ltd., headquartered in Meguro, Japan. They use Yamaha Corporation's Vocaloid 3 singing synthesizer technology. Her voice is sampled by Lia.
2 KAITO KAITO is a humanoid persona voiced by a singing synthesizer application developed by Yamaha Corporation using their new Vocaloid singing synthesizer technology under the codename of "Taro".

Even with a V3 update, he still doesn't have as of a good voice as others.

3 MEIKO (Vocaloid) MEIKO is a humanoid persona voiced by a singing synthesizer application called Vocaloid developed by Yamaha Corporation.
4 Lily (Vocaloid) Lily (リリィ) is a female Vocaloid created by Internet Co., Ltd., done in collaboration with Avex Management Co., Ltd and YAMAHA Corporation, and was initially released in August 2010 for the VOCALOID2 engine. There has since been a second installment developed for the VOCALOID3 engine and dubbed V3 Lily. She is voiced by the Japanese female singer, musician and performance artist, Yuri Masuda (益田祐里; Masuda Yuri).

Despite Lily not being my favorite out all these I do feel like she's been very neglected and has potential especially since shes been around for a long time and has grown a fanbase around her.

5 Piko Utatane
6 CUL (Vocaloid)
7 MAYU (Vocaloid) MAYU is a female Vocaloid created by EXIT TUNES Co., Ltd. She generally has mixed reception. She is voiced by Mayumi Morinaga.
8 Ryuto Ryuto is a male Vocaloid created by Internet Co., Ltd. He is the mascot of Gachapoid. Despite not being a failure, he generally has negative reception. He is voiced by Kuniko Amemiya.
9 YOHIOloid Yohioloid is an English Vocaloid developed by PowerFX who also has an additional Japanese voice bank. The vocalist sampled for his vocals was Swedish singer Yohio.
10 OLIVER (Vocaloid)
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