I run Bitcoin Core 0.14.1, for Segwit they tell me to "upgrade" to 0.13.1. So confusing
Yes, it means 0.13.1 or later. All versions of Bitcoin Core since enforce the SegWit rules. The upgrade guide was written when only 0.13.1 was available, but since then 0.13.2, 0.14.0, 0.14.1, and 0.14.2 were released. Version 0.15.0 will be released soon.

I've filed an issue to get the page clarified: https://github.com/bitcoin-core/bitcoincore.org/issues/411