*508The petitioner, Luis Ariel Rivera, appeals, following the granting of his petition for certification to appeal, from the judgment of the habeas court dismissing his petition for a writ of habeas corpus for lack of jurisdiction pursuant to Practice Book § 23-29 (1).1 On appeal, the petitioner claims that (1) the habeas court's articulation constitutes an improper modification of its original judgment and must be stricken from the record, and (2) the habeas court improperly dismissed his petition for lack of jurisdiction. We conclude that the habeas court lacked jurisdiction over the petition and, accordingly, affirm the judgment.
The following procedural and statutory background is relevant to this appeal. In 2007, the petitioner was arrested and charged with manslaughter in the first degree in violation of General Statutes § 53a-55.2 In *5092009, the petitioner pleaded guilty to that charge and was sentenced to twenty years of incarceration, execution suspended after fifteen years, followed by five years of probation. As a result of his conviction, the petitioner remains in the custody of the respondent, the Commissioner of Correction.
In 2011, while the petitioner was incarcerated, the General Assembly enacted No. 11-51, § 22, of the 2011 Public Acts (P.A. 11-51), later codified in General Statutes § 18-98e (original legislation).3 The *703original legislation provided that certain classes of prisoners, which included the petitioner, convicted of crimes committed on or after October 1, 1994, "may be eligible to earn risk reduction credit toward a reduction of such person's sentence, in an amount not to exceed five days per month, at the discretion of the Commissioner of Correction" for certain positive, statutorily described conduct. *510P.A. 11-51, § 22. The original legislation also conferred on the respondent the discretion to revoke earned (and even unearned) risk reduction credits for good cause. P.A. 11-51, § 22.4 Because a sentence for a violation of § 53a-55 was not disqualifying at the time, the original legislation rendered the petitioner eligible to earn risk reduction credit toward the advancement of his end of sentence date. In 2015, the General Assembly passed No. 15-216, § 9, of the 2015 Public Acts (P.A. 15-216), which amended § 18-98e to expand the list of persons ineligible to earn risk reduction credit toward the reduction of their sentences, including persons who have been sentenced for violating § 53a-55,5 the offense of which the petitioner had been convicted. Consequently, once the amendment became effective on October 1, 2015, the petitioner was no longer eligible to earn risk reduction credit toward the reduction of his sentence. See P.A. 15-216, § 9.
On December 11, 2015, the petitioner, representing himself, filed his petition alleging that the application of P.A. 15-216 resulted in "[d]iscrimination" and "the violation of ex post facto."6 He alleged that, as of October 1, 2015, he became ineligible to earn risk reduction *511credit toward the reduction of his sentence, even though he had been earning such credit since the original legislation went into effect.7 The *704petitioner does not claim that he has been deprived of risk reduction credit already earned. On December 21, 2015, the habeas court dismissed the petition, sua sponte, pursuant to Practice Book § 23-29 (1), for lack of jurisdiction "over the claims set forth in the petition concerning the change in the [p]etitioner's eligibility date for parole consideration." The court did not hold a hearing prior to dismissing the petition.
On December 31, 2015, the petitioner filed a petition for certification to appeal, contending that his petition was dismissed based on a ground not raised therein. On January 4, 2016, the habeas court granted the petition for certification to appeal. On January 11, 2016, the petitioner filed a request for the appointment of counsel and an application for waiver of fees, costs, and expenses. On January 13, 2016, the habeas court granted his request for appointment of counsel and application for waiver. This appeal followed.
On May 31, 2016, the petitioner filed a motion for articulation, stating that "[t]he need for an articulation *512motion arises from the fact that the dismissal refers to a parole eligibility claim, and the claim raised is not such a claim. Articulation is needed because it is not clear how the perceived lack of jurisdiction over a 'change in the petitioner's eligibility date for parole consideration' pertains to the dismissal of a claim unrelated to parole eligibility." On July 12, 2016, the habeas court denied the motion for articulation. On July 19, 2016, the petitioner filed with this court a motion for review of the denial of his motion for articulation. On September 21, 2016, this court granted in part the petitioner's motion for review and ordered the habeas court "to articulate the legal basis for the court's determination that it lacks jurisdiction over the claims set forth in the petition concerning the change in the petitioner's eligibility for parole consideration."
On January 17, 2017, in accordance with this court's order, the habeas court issued an articulation. The habeas court concluded that the application of P.A. 15-216 to the petitioner does not violate the ex post facto clause because it does not increase his term of confinement. The habeas court also concluded that the prospective opportunity to earn risk reduction credit pursuant to § 18-98e, as amended by P.A. 15-216, does not implicate a liberty interest upon which the petitioner may predicate habeas relief because the legislative amendment has at its foundation discretionary language authorizing, but not requiring, the respondent to grant such credit to qualifying inmates.
I
We first address the petitioner's claim that the habeas court improperly dismissed his petition for lack of jurisdiction.8 The petitioner argues that, pursuant to the *513proper jurisdictional analysis, the allegations in his petition are sufficient to invoke the jurisdiction of the habeas court. Additionally, the petitioner argues that a liberty interest in future unearned risk reduction credit is not required to establish *705jurisdiction over his discrimination9 and ex post facto claims. The respondent argues, to the contrary, that the habeas court properly dismissed the petition for lack of subject matter jurisdiction because the petitioner lacks a cognizable liberty interest in earning future risk reduction credit, and there is no colorable basis for an ex post facto claim. We agree with the respondent.
To begin, we set forth the relevant standard of review and legal principles that govern the petitioner's claim on appeal. "[A] determination regarding a trial court's subject matter jurisdiction is a question of law and, therefore, we employ the plenary standard of review and decide whether the court's conclusions are legally and logically correct and supported by the facts in the record." (Internal quotation marks omitted.) Petaway v. Commissioner of Correction , 160 Conn. App. 727, 731, 125 A.3d 1053 (2015), cert. dismissed, 324 Conn. 912, 153 A.3d 1288 (2017). "[T]o invoke the trial court's subject matter jurisdiction in a habeas action, a petitioner must allege that he is illegally confined or has been deprived of his liberty." (Internal quotation marks omitted.) Joyce v. Commissioner of Correction , 129 Conn. App. 37, 41, 19 A.3d 204 (2011) ; see also Perez v. Commissioner of Correction , 326 Conn. 357, 368, 163 A.3d 597 (2017) (to invoke habeas court's jurisdiction, petitioner must allege interest sufficient to give rise to *514habeas relief). "In order ... to qualify as a constitutionally protected liberty ... the interest must be one that is assured either by statute, judicial decree, or regulation." (Emphasis in original; internal quotation marks omitted.) Vitale v. Commissioner of Correction , 178 Conn. App. 844, 867-68, 178 A.3d 418 (2017), cert. denied, 328 Conn. 923, 181 A.3d 566 (2018).
As this court previously has explained, "[o]ur appellate courts have concluded, consistently, that an inmate does not have a constitutionally protected liberty interest in certain benefits-such as good time credits, risk reduction credits, and early parole consideration-if the statutory scheme pursuant to which the commissioner is authorized to award those benefits is discretionary in nature." Green v. Commissioner of Correction , 184 Conn. App. 76, 86-87, 194 A.3d 857 (2018) ; see Holliday v. Commissioner of Correction , 184 Conn. App. 228, 235, 194 A.3d 867, A.3d (2018) (habeas court properly dismissed for lack of subject matter jurisdiction ex post facto claim based on 2013 statutory change regarding application of earned risk reduction credit toward parole eligibility); see also Perez v. Commissioner of Correction , supra, 326 Conn. at 370-73 (no liberty interest in early parole eligibility or risk reduction credit); Petaway v. Commissioner of Correction , supra, 160 Conn. App. at 733-34 (affirming judgment of habeas court based on lack of jurisdiction over ex post facto claim asserted in absence of allegation that 2013 statutory change regarding parole eligibility extended length of incarceration or delayed parole eligibility beyond time periods that existed at time of offense); Abed v. Commissioner of Correction , 43 Conn. App. 176, 182-83, 682 A.2d 558 (petitioner failed to state cognizable ex post facto claim based on prospective denial of discretionary, *706statutory good time credits), cert. denied, 239 Conn. 937, 684 A.2d 707 (1996). *515In the present case, the statutory scheme that created the opportunity to earn risk reduction credit did not exist at the time of the petitioner's offense. It was not until 2011, upon the passage of the original legislation, that the petitioner became eligible to earn risk reduction credit toward the reduction of his sentence pursuant to § 18-98e. Although the petitioner was no longer eligible to earn risk reduction credit after the passage of P.A. 15-216, the 2015 amendments did not increase the petitioner's overall sentence. Rather, the 2015 amendments simply returned the petitioner to the position that he was in at the time of his offense. See Perez v. Commissioner of Correction , supra, 326 Conn. at 378-80 (ex post facto inquiry requires comparison of challenged statute with statute in effect at time of offense).
Furthermore, during the period in which the petitioner was eligible to earn risk reduction credit pursuant to § 18-98e, such credit could be awarded only at the discretion of the respondent. See P.A. 11-51, § 22 ("any person sentenced to a term of imprisonment for a crime committed on or after October 1, 1994, and committed to the custody of the Commissioner of Correction on or after said date ... may be eligible to earn risk reduction credit toward a reduction of such person's sentence ... at the discretion of the Commissioner of Correction"); General Statutes (Rev. to 2013) § 18-98e (same). That is, the interest in earning risk reduction credit, as alleged by the petitioner, was not assured by § 18-98e at any time. Accordingly, the petitioner has not alleged a constitutionally protected liberty interest that would give rise to habeas relief. We conclude, therefore, that the habeas court lacked subject matter jurisdiction over the petitioner's ex post facto claim, and the petition was properly dismissed. See Perez v. Commissioner of Correction , supra, 326 Conn. at 369 ("if the habeas court reached the correct decision, but on mistaken grounds, *516this court will sustain the habeas court's action if proper grounds exist to support it").
II
We next turn to the petitioner's claim that the habeas court's articulation improperly modified its original judgment and must be stricken from the record. The petitioner contends that, rather than issuing a proper articulation, the habeas court improperly offered an entirely new legal basis for its original judgment of dismissal. The petitioner argues further that the habeas court issued its modified decision more than four months after the original judgment in violation of General Statutes § 52-212a. Because we conclude, in part I of this opinion, that the habeas court lacked subject matter jurisdiction over the petitioner's claims regarding his eligibility to earn risk reduction credit pursuant to § 18-98e, we need not address the petitioner's remaining contention that the habeas court's articulation constitutes an improper and untimely modification of the original judgment of dismissal. See id.
The judgment is affirmed.
In this opinion the other judges concurred.