Sorry to hear about that, as per the new Rules, users are not recommended to reply article comments older than 3 months. However, your action is merely not encouraged (aka it is not forbidden). Hopefully this will clarify everyone's concern.
If you reply to an old comment, we may remind you not to reply in future because we do not recommend users doing this. Since this is not a punishable offence, you will receive nothing other than a kind reminder from moderators or admins.