Best way to learn about recent (non-breaking) changes in ggplot2 is to rerun your old R code. Now I know that :
Using `size` aesthetic for lines was deprecated in ggplot2 3.4.0. Please use `linewidth` instead.
The `<scale>` argument of `guides()` cannot be `FALSE`. Use "none" instead as of ggplot2 3.3.4.
Other than that, I found that the theme_minimal() is as good as the hrbrthemes:theme_ipsum. Less dependencies, clear and elegant graphical output.