Hello Tomaszu, On 9/14/17 2:14 PM, Tomasz Stokowy wrote: > > Could you suggest how to avoid this warning? I would like to use both hg19 and hg38 references in my package. super easy: library(BSgenome.Hsapiens.UCSC.hg19) suppressMessages(library(BSgenome.Hsapiens.UCSC.hg38))