## upgrade.CONFIG_VERSION


The `[tether] version` this code writes and expects. `tether upgrade` brings


`upgrade.CONFIG_VERSION=``5`


older datasets forward (see `tether.upgrade`; removed at 0.1.0). 5 is 0.1.0b4's: what 0.1.0b3 recorded under identities and states that changed is carried forward, and a 0.1.0b3 refuses the dataset from then on.