Starlight 1.16.5 belongs to the project’s early development period, before the later 1.17–1.20 public release line became the best-known part of the mod. That makes 1.16.5 a legacy target: the right question is not “does Starlight exist?” but “is the exact build, loader and world state safe for this profile?”
Why 1.16.5 needs extra care
Older Minecraft modding environments are more sensitive to loader revisions, mixin differences and mod interactions. A file compiled from an old branch can be technically related to 1.16.5 while still being a poor match for your exact loader or modpack.
Use the loader as a hard compatibility gate
Do not move a Fabric build into a Forge profile or the reverse. Before adding Starlight, record the Minecraft version, loader name, loader version and Java version used by the existing pack.
Check the lighting stack
Starlight and Phosphor are incompatible as simultaneous light-engine replacements. If a modpack already contains a lighting optimization, identify it before changing anything.
Test on a copied world
Launch a duplicate save, visit previously generated chunks, cross chunk borders at night, place and remove light sources, and watch for delayed or incorrect light updates. If behavior differs from the original profile, revert the test rather than repeatedly changing multiple mods at once.
Do not treat a source archive as a mod file
The download supplied on this site is a source ZIP for the archived Fabric branch. A source tree is not a ready-to-run JAR. Legacy users should avoid renaming ZIP files or placing source archives in the mods directory.
Related guides
Use the common-errors guide for a clean diagnosis order and the download guide to understand archive versus release files.