We're getting there, conda packages work again... However, I forgot to delete an assert statemente introduced for debugging ¯_(ツ)_/¯
All of v0.8.1 - v0.8.4 are very minor fixes on top of /changelog/v0.8.0; read those release notes.
As a fix, this version also changes a default parameter: SingleSiteDMRG now uses a mixer by default.