The substantive issue in this appeal is whether the expiration of a public employee’s term of office divests a municipal board of ethics of the authority to continue an investigation into alleged official misconduct during the term of public employment. The plaintiff, Thom Serrani, brought an action for declaratory and injunctive relief to prevent the defendant, the board of ethics of the city of Stamford, from exercising continuing jurisdiction to investigate his conduct during his expired term of office as mayor. The trial court, after an evidentiary hearing, denied the plaintiff’s application for a temporary injunction. The plaintiff then moved the court to render judgment in favor of the defendant. Despite the defendant’s objection, the trial court granted the plaintiff’s motion. The plaintiff appealed from the judgment of the trial court to the Appellate Court, and we transferred the appeal to this court pursuant to Practice Book § 4023 and General Statutes § 51-199 (c). Because we conclude that the trial court did not have jurisdiction to render a judgment on the present record, we reverse and remand the case for further proceedings.
The procedural history of this case is undisputed. As the trial court observed in its memorandum of decision denying the plaintiff’s application for a temporary injunction, the plaintiff’s complaint sought injunctive relief as part of a claim for a declaratory judgment.1 *307After the trial court’s denial of the temporary injunction, the plaintiff moved the trial court to render judgment in favor of the defendant. The plaintiff represented to the court that he had no further evidence or argument to offer to advance his claim that § 15 of the Stamford Municipal Code of Ethics 2 is unenforceable in the circumstances of his case. Although the defendant objected, seeking the opportunity to bolster further its arguments to sustain the validity of § 15, the trial court granted the plaintiff’s motion and rendered judgment for the defendant.3
*308A declaratory judgment action was the proper way to raise the plaintiffs challenge to the validity of § 15 of the Stamford Municipal Code of Ethics, which purports to authorize the defendant, upon an affirmative vote, to exercise continued jurisdiction over officials after they have left municipal office. See Bombero v. Planning & Zoning Commission, 218 Conn. 737, 742-43, 591 A.2d 390 (1991). The jurisdiction of the trial court over declaratory judgment actions depends upon compliance with the notice requirement of Practice Book § 390 (d). That section provides in relevant part: “The court will not render declaratory judgments upon the complaint of any person . . . (d) unless all persons having an interest in the subject matter of the complaint . . . have reasonable notice thereof.” Failure to comply with § 390 (d) deprives the trial court of subject matter jurisdiction to render a declaratory judgment. See, e.g., Connecticut Ins. Guaranty Assn. v. Raymark Corporation, 215 Conn. 224, 229, 575 A.2d 693 (1990); Benz v. Walker, 154 Conn. 74, 77, 221 A.2d 841 (1966). “[JJurisdiction of the subject matter is a question of law and cannot be waived or conferred by consent either in the trial court or here. . . . Once brought to the attention of the court, regardless of the form of the motion, it must be acted upon.” (Internal quotation marks omitted.) In re Judicial Inquiry No. 85-01, 221 Conn. 625, 629, 605 A.2d 545 (1992); Practice Book §§ 143, 145.
Because neither the Supreme Court record nor the trial court file disclosed compliance with § 390 (d), this court asked the parties for clarification. Without conceding the existence of any jurisdictional difficulty, the plaintiff offered to effect a cure by withdrawing his sec*309ond request for declaratory relief,4 thereby purporting to limit his claim to one directly addressing only his own right to relief from the defendant’s continued exercise of investigatory authority after his departure from mayoral office.
We need not decide whether a partial withdrawal of the plaintiff’s complaint, if it had predated the purported rendering of a final judgment in this case, would have allowed him to bypass the notice requirements for a declaratory judgment. The lack of subject matter jurisdiction to render a final judgment cannot be cured retrospectively. Circle Lanes of Fairfield, Inc. v. Fay, 195 Conn. 534, 540, 489 A.2d 363 (1985). The judgment presently on appeal must, therefore, be set aside.
Our conclusion that the trial court lacked subject matter jurisdiction to render its declaratory judgment does not, however, require a dismissal of the plaintiffs action on remand. A jurisdictional defect relating to notice can be remedied in any of the ways noted in Connecticut Ins. Guaranty Assn. v. Raymark Corporation, supra, 230.5 Notably, the plaintiff may ask for an order of notice in order to comply with the procedural requirements of the Practice Book with respect to individuals whose identity might otherwise be difficult to ascer*310tain. Once there has been compliance with § 390 (d),6 the trial court will have plenary authority to render whatever judgment it then deems appropriate. Id.
The judgment is reversed and the case is remanded for further proceedings consistent with this opinion.
The plaintiff’s substitute request for relief expressly seeks a declaratory judgment. It requests: “1. A declaratory judgment determining that the Defendant lacks jurisdiction over the Plaintiff;
“2. A declaratory judgment determining that § 15 of the Code of Ethics of the City of Stamford is illegal to the extent that it purports to authorize *307the Defendant’s continued jurisdiction over former employees or officers of the City of Stamford;
“3. A declaratory judgment declaring null and void the action of the Defendant taken on February 29,1992, purporting to continue jurisdiction over the Plaintiff;
“4. A declaratory judgment declaring null and void any and all action of the Defendant taken subsequent to February 29, 1992, purporting to render a decision and/or finding of facts regarding the Plaintiff;
“5. A temporary and permanent injunction enjoining the Defendant and its members, agents and employees from exercising or purporting to exercise jurisdiction over the Plaintiff;
“6. Such other and further relief in law or equity as the Court deems appropriate.”
Section 15 of the Stamford Municipal Code of Ethics, Stamford Code of Ordinances No. 640 Sup. (1989), provides: “JURISDICTION If an officer or employee under investigation leaves office, or employment, the Board by a majority vote shall have the power to continue the investigation.”
On February 29, 1992, the defendant voted, by the requisite majority, to continue investigation of the official conduct of the plaintiff after the expiration of his term as mayor.
The plaintiff filed the motion for judgment on April 13,1992. Also on that day, he filed an amended complaint containing a substitute request for relief in response to the defendant’s April 10, 1992 request to revise the plaintiff’s complaint. The plaintiff also filed an application to the chief justice for certification to appeal pursuant to General Statutes § 52-265a, which was denied by Associate Justice David M. Shea on April 14, 1992.
On April 22,1992, when the motion for judgment was granted, the defendant had not yet filed an answer to the complaint. The pleadings were, therefore, not closed. In response to an inquiry by this court about the jurisdictional consequences of the fact that the pleadings had not been closed; see Pendiman Corporation v. White Oak Corporation, 195 Conn. 393, 397-98, 488 A.2d 449 (1985); Doublewal Corporation v. Toffolon, 195 Conn. *308384, 391-92, 488 A.2d 444 (1985); the defendant at oral argument waived its objection to appellate consideration of the merits of the plaintiff’s substantive claim. We need not, in this case, decide the effectiveness of such a waiver.
See footnote 1.
Our decision in Connecticut Ins. Guaranty Assn. v. Raymark Corporation, 215 Conn. 224, 230, 575 A.2d 693 (1990), that a trial court may entertain procedural efforts to cure a jurisdictional defect with regard to the giving of notice under Practice Book § 390 finds support in the language of the Practice Book provision. Section 390 explicitly states that the “court will not render declaratory judgments upon the complaint of any person . . . unless all persons having interest in the subject matter of the complaint are parties to the action or have reasonable notice thereof.” (Emphasis added.) Unlike other jurisdictional defects implicating the trial court’s subject matter jurisdiction, therefore, the bringing of a declaratory judgment action is not itself precluded by a failure to comply with the notice requirement. To the extent that State ex rel. Kelman v. Schaffer, 161 Conn. 522, 528, 531, 290 A.2d 327 (1971), is to the contrary, it is overruled.
Presumably the trial court will also ascertain that the pleadings have been closed. See footnote 3.