Library Symbol update declined in Sketch: no documented way to roll an instance back to a prior Library version

In Sketch (recent versions, Workspace documents), Symbols from a shared Library can be updated in place, and documents referencing them show an update prompt rather than applying changes silently. Overrides on text, images, and nested Symbols are preserved per instance.

The unresolved case: once a Library update is accepted and the document is saved, there appears to be no documented per-instance mechanism to return a single Symbol instance to the earlier Library version. Undo is session-scoped and lost when the document closes, and detaching the instance only converts it to ordinary layers. Workspace version history can restore an earlier whole-document state, but that reverts everything, not just the one Symbol.

Assuming a current Sketch release and a Workspace-saved document:

• Is there any supported way to roll back one Symbol instance to a previous Library version without restoring the entire document from version history?
• If the Library source itself is reverted, do linked documents surface a new update prompt so instances converge back, or can they get stuck on the newer state?
• Does declining the update prompt leave instances pinned to the last-rendered state indefinitely, and is that behavior documented?