We usually add the version information, for example:
"Deprecated since v1.4; it was more confusing than useful, use `[]=`".
Unfortunately not in your case though...
Found it! 1.6.0 was the version it was introduced.
when NimVersion >= "1.6.0":
someseq.delete(a..b)
else:
someseq.delete(a,b)
Thank you.