Last verified "Legacy": 1.9.10 (May 11, 2021)

First verified "2023": 2.2.2 (Oct 24, 2023)

Without evidence to the contrary, "Legacy" is now "≤ 1.9.10" and "2023 Version" is now "2.2.2+"

Sources:

1. https://web.archive.org/web/20231015160731/https://play.google.com/store/apps/details?id=com.ketchapp.donttouchthespikes
2. https://www.apk4fun.com/history/14798/
3. https://dont-touch-the-spikes.en.uptodown.com/android/versions
4. https://apkcombo.com/don-t-touch-the-spikes/com.ketchapp.donttouchthespikes/old-versions