is newer than the R version used to build bindrcpp. The solution is to reinstall bindrcpp. Almost always, it doesn't matter about the differing versions, but there are always edge cases. My general rule, is if the second number differs, e.g. R3.5 vs R3.4 I would reinstall. It doesn't take that long.
Is it a bad idea to just load bindrcpp explicitly with library(bindrcpp) to avoid getting these warnings?
For the reason above, I don't see why this would work.
As @mara mentioned, you can use suppressWarnings(). However, I try to never use this and instead fix the issue at the source.