The msos R package serves as the companion package to Professor Emeritus John Marden’s Multivariate Statistics: Old School, which is used in STAT 571: Multivariate Analysis course at the University of Illinois at Urbana-Champaign (UIUC). In this hotfix, a long standing bug in the lda() routine that affected unbalanced data was corrected thanks to Trevor Park who reported the issue! Moreover, the package has switched from being tested with TravisCI to using GitHub Actions and now has its own pkgdown website at: …