Dynamic String Concat (legacy)

Found a node in your saved workflow called DynamicStringConcat and a "(legacy)" warning next to it? Relax - it's the current node, just registered under MoonPack v0.1's old key. In v0.2 the pack renamed everything to a MoonPack_ prefix, and DynamicStringConcat became MoonPack_DynamicStringConcat. The old key still works, which is why your workflow loads at all.

The full details are on the MoonPack_DynamicStringConcat page. The short version: it's a string joiner whose input slots auto-expand as you plug in more connections - no more rebuilding a node because you need a fourth text input - plus a template mode where {1}, {2} placeholders interpolate instead of plain joining, with separator, prefix, suffix, whitespace stripping, and empty-skipping around the edges. One text output feeds your CLIP encoder.

Why the legacy label is actually useful to know

The rename story is the thing people trip on, so it's worth stating plainly: MoonPack v0.2 kept the old DynamicStringConcat key registered as an alias for exactly one release cycle, and the README says the aliases are scheduled for removal in 1.0. If your workflow still references the legacy key, the fix is one save: load it, hit save, and ComfyUI rewrites the graph using MoonPack_DynamicStringConcat. After that, a future pack update can't break the graph.

Also worth knowing if you're comparing options: this node's main rival is kjnodes' Join String Multi, which shows up in community threads whenever someone asks about concatenating strings in ComfyUI. Both auto-expand; MoonPack's edge is the template interpolation mode. If MoonPack is already in your folder, that's one less pack to install.

Installing it

It comes with the pack, either way:

cd ComfyUI/custom_nodes
git clone https://github.com/moonwhaler/comfyui-moonpack.git

or ComfyUI Manager → MoonPack → install, restart. Under MoonPack/string. No models, no third-party Python dependencies - the pack is deliberately dependency-free beyond what ComfyUI ships.

Bottom line

The "(legacy)" is a naming artifact, not a warning that the node is obsolete. It works, it's the same node as the prefixed one, and the only action required of you is the one re-save that migrates your workflow to the new key.