Looking for LineageOS 17.1 download link for vivalto3gvn (Samsung Galaxy V/Ace NXT/Trend Neo) According to stats.lineageos.org, the Samsung model codename vivalto3gn has OS versions of 13.0, 15.1 and 17.1. I did a little more searching, but I couldn't find download links for 15.1 and 17.1. The latest version I can find is 14.1 from this website. Do these versions really exist or are they caused by reporting errors?
Your device was never supported by LineageOS officially. The old 14.1 version seems to be an unofficial version which means that typically one developer who owns the phone implemented the necessary changes for making LineageOS work on your device, but if those changes were ever published is unknown.
Why there are no newer versions is unclear, may be the device hardware was too restricted (it has only 512MB RAM which is way too small for modern Android versions) or the developer who created the 14.1 version got a new device and lost interest in developing new versions for the old device.
In the end you have to take it as it is, there is one 14.1 version for your device but nothing newer.