Short answer. Yes, but only with the court's permission. Rule 10, Section 6 lets you move for leave to file a supplemental pleading covering transactions, occurrences, or events that happened after your original pleading, on reasonable notice and terms the court finds just; the other side then has ten calendar days from the admitting order to respond.
What the law says
Upon motion of a party[,] the court may, upon reasonable notice and upon such terms as are just, permit him or her to serve a supplemental pleading setting forth transactions, occurrences or events which have happened since the date of the pleading sought to be supplemented.
Rule 10, Section 6 — Supplemental pleadings. Read the full provision →
What the law says
The adverse party may plead thereto within ten calendar days from notice of the order admitting the supplemental pleading.
Rule 10, Section 6 — Supplemental pleadings. Read the full provision →
What a supplemental pleading is for
A supplemental pleading is not a rewrite of your complaint — it is an addition that covers events which happened since the date of the pleading sought to be supplemented. If your original complaint alleged a breach that has since continued, escalated, or produced new consequences, a supplemental pleading is the mechanism for putting those later developments before the court in the same case, instead of leaving them out or starting an entirely separate action over facts that grew out of the same dispute.
You need the court's leave first
Section 6 does not let a party simply file new material on their own initiative. It requires a motion of a party, and the court decides whether to allow it based on reasonable notice to the other side and on terms as are just. That gives the judge room to set conditions — for example, on timing or on what else must be filed alongside it — rather than admitting a supplemental pleading automatically the moment it is offered.
The other side's deadline to respond
Once the court issues the order admitting the supplemental pleading, the adverse party has ten calendar days from notice of that order to plead in response. That is a short, fixed window measured from the order itself, not from when the supplemental pleading was originally filed or served, so the clock only starts running once the court has actually acted on the motion.
Why this differs from simply amending your pleading
An amendment typically corrects or restates something that was already true, or should have been alleged, as of the original filing. A supplemental pleading instead brings in facts that did not yet exist when the case began. That distinction matters practically: if the new material predates your complaint, you are usually looking at an amendment; if it genuinely happened afterward, Section 6's supplemental-pleading route, with its own motion and notice requirements, is the one that actually fits.