As you can see from our EOL page:
The EOL for Snort 18.104.22.168 is approaching in a couple days. From our download statistics, the percentage of people is pretty small.
Please try and update your engines this week to 22.214.171.124, the current version. We also look forward to the release of 126.96.36.199 in the coming weeks, so for those of you still on 188.8.131.52, the EOL for 184.108.40.206 will be the release of 220.127.116.11 + 90 days (as a reminder).
So, 18.104.22.168 users, your EOL is coming too, and there are tens of thousands of you on that version. It's upgrade time!