4.13.1:
# true or false;;
Alert deprecated: Stdlib.or
Use (||) instead.
- : bool = true
Manual says it is deprecated. Yet 5.1:
# true or false;;
Error: Unbound value or
# let or = "foo";;
Error: Syntax error
# let (or) = "foo";;
val ( or ) : string = "foo"
Looks like it is still reserved as an operator. Which was pointed out above.