On the heels of the reported musical chairs shuffle of designers and employees between Shuguang, PSVANE, and TFJM downsizing of tubes, and the Shuguang factory fire, there seemed to be reports of uncertainty about production 2019-2020.
It was also hard to tell what was leftover inventory at online retail sellers in 2020-2021, and then supplies of various tubes seemed to be "out of stock" just after COVID it us all. Around mid 2021-2022 started seeing new version Shuguang, PSVANE, Linlai tubes, started showing up for sale again. Some reporting Shuguang was not fully shut down and still in production with "some" tubes, not all. My newer latest version MKII PSVANE small signal tubes sounding better than versions prior to 2017. Fast forward 2022, various new tubes showing up again.