diff --git a/Vectors.Rmd b/Vectors.Rmd
index c1adf8b89..a06fa096e 100644
--- a/Vectors.Rmd
+++ b/Vectors.Rmd
@@ -702,7 +702,7 @@ df <- data.frame(
 str(df)
 ```
 
-Beware of the default conversion of strings to factors. Use `stringsAsFactors = FALSE` to suppress this and keep character vectors as character vectors:
+If you are using a version of R before 4.0.0, beware of the default conversion of strings to factors. Use `stringsAsFactors = FALSE` to suppress this and keep character vectors as character vectors:
 
 ```{r}
 df1 <- data.frame(