This .html output from Rmarkdown that describes the update of invitrodb between versions 3.5 and 4.1. Invitrodb version 4.1 represents the first full release of the ToxCast database in a new schema designed to accommodate the R package dependency, tcplFit2, which is used in curve-fitting and hit-calling of multi-concentration response data. This invitrodb schema was beta-tested with our research release of invitrodb v4.0 to accompany the manuscript, “The ToxCast Pipeline: Updates to Curve-Fitting Approaches and Database Structure” and release of tcpl v3.0.1.