What makes a change legally relevant?
For a utility patent, identify the claim limitation the proposed change is intended to avoid and document how the revised product works. Under Warner-Jenkinson Co. v. Hilton Davis Chemical Co., equivalents must also be considered element by element. A new label or a different overall purpose does not itself answer that comparison.
How can the prosecution history help?
Festo Corp. v. Shoketsu Kinzoku Kogyo Kabushiki Co. explains how narrowing amendments can limit the reach of equivalents. Review the relevant amendments and reasons with counsel instead of assuming that every nonliteral change falls outside the patent.
Does a new version resolve earlier sales?
Analyze the versions and dates separately. Section 271(a) addresses acts involving the patented invention during its term. A change to a future product does not, by itself, answer an allegation about the earlier product. Keep dated specifications, samples, and shipment records for both.
What if an injunction already exists?
Read its specific terms and obtain advice about the proposed revision before shipping. Rule 65(d) governs the required specificity and persons bound by a federal injunction. Do not rely solely on an internal conclusion that the revision is different enough.