*863The petitioner, Fabian Richards, appeals from the judgment of the habeas court denying his petition for a writ of habeas corpus. In his petition, the petitioner alleged that his criminal trial counsel had provided ineffective assistance by failing to advise the petitioner adequately of the immigration consequences he faced by entering a guilty plea. Because the petitioner already has been deported to Jamaica, pursuant to a deportation order issued by the United States Immigration Court, and has failed to establish that any practical relief could be provided by this court, we conclude that his appeal is moot. Accordingly, the appeal is dismissed.
The petitioner is a native of Jamaica, who lawfully entered this country on January 8, 2007, on a visitor visa. He married a citizen of the United States and received permanent resident status in 2010. In 2012, the petitioner entered guilty pleas to charges of second degree assault in violation *442of General Statutes § 53a-60 (a)(2) and carrying a pistol without a permit in violation of General Statutes § 29-35(a). Subsequently, he brought this habeas petition alleging that his trial counsel rendered ineffective assistance by failing to advise him adequately of the immigration consequences of his *864plea. The habeas court denied his petition but granted certification to appeal, and the petitioner filed the present appeal.
Several months after the petitioner had filed his appellate brief, the respondent, the Commissioner of Correction, on October 1, 2015, submitted to the Appellate Court clerk's office a letter that stated: "The Commissioner respectfully requests that the clerk bring the following matter to the court's attention. During the pendency of this appeal, the petitioner has been deported from the United States to Jamaica pursuant to an immigration court deportation order. This is a relevant fact for the court's consideration under State v. Aquino, 279 Conn. 293, 901 A.2d 1194 (2006), and St. Juste v. Commissioner of Correction, 155 Conn.App. 164, 109 A.3d 523, cert. granted, 316 Conn. 901, 111 A.3d 470 (2015)."
The respondent also submitted a letter of supplemental authority, stating that it may also refer to 8 U.S.C. § 1229b (a), 8 U.S.C. § 1229b (d), 8 U.S.C. § 1182(a)(2)(A), and 8 U.S.C. § 1182(a)(2)(C). The respondent contends that the appeal is moot. The petitioner's counsel concedes that the petitioner has been deported, but argues that the matter is not moot.1 We agree with the *865respondent that the appeal is moot because there is no practical relief that can be afforded the petitioner.
"Under our well established jurisprudence, [m]ootness presents a circumstance wherein the issue before the court has been resolved or had lost its significance because of a change in the condition of affairs between the parties.... In determining mootness, the dispositive question is whether a successful appeal would benefit the plaintiff or defendant in any way.... In other words, the ultimate question is whether the determination of the controversy will result in practical relief to the complainant.... Mootness implicates [this] court's subject matter jurisdiction and is thus a threshold matter for us to resolve." (Citation omitted; internal quotation marks omitted.) State v. Jerzy G., 162 Conn.App. 156, 161, 130 A.3d 303 (2015), cert. granted, 320 Conn. 919, 132 A.3d 1093 (2016).
For a deported petitioner to establish that an appeal is not moot, our Supreme Court has stated that the petitioner is required to establish that the underlying conviction was the exclusive basis of his or her deportation. State v. Aquino, supra, 279 Conn. at 298, 901 A.2d 1194 ; see State *443v. Jerzy G., supra, 162 Conn.App. at 161-64, 130 A.3d 303 (following rule of Aquino ); Paulino v. Commissioner of Correction, 155 Conn.App. 154, 162-63, 109 A.3d 516 (same), cert. denied, 317 Conn. 912, 116 A.3d 310 (2015) ; Quiroga v. Commissioner of Correction, 149 Conn.App. 168, 173, 87 A.3d 1171 (same), cert. denied, 311 Conn. 950, 91 A.3d 462 (2014) ; State v. Chavarro, 130 Conn.App. 12, 17-18, 21 A.3d 541 (2011) (same); but see St. Juste v. Commissioner of Correction, supra, 155 Conn.App. at 174, 109 A.3d 523 (petitioner must prove both that underlying conviction was exclusive basis for deportation and that petitioner would be permitted reentry in absence of underlying conviction). "If [the deportation] was not the result of his guilty plea alone, then this court can grant no practical relief and any decision rendered by *866this court would be purely advisory." State v. Aquino, supra, 279 Conn. at 298, 901 A.2d 1194.
In the present case, the respondent argues that on the basis of the present record, we cannot ascertain the basis for the petitioner's deportation. The petitioner argues that we know the basis because he has no convictions other than those underlying the present case. We agree with the respondent.
Although the December 28, 2012 notice to appear, issued by the Department of Homeland Security, was based on the petitioner's underlying convictions in the present case, we do not have an official copy of the decision of the United States Immigration Court giving us the basis for its ruling deporting the petitioner, and the order, itself, does not contain the basis. See footnote 1 of this opinion. Indeed, Aquino requires proof that the conviction being challenged is "the exclusive basis of the petitioner's deportation, rather than a primary or likely one." Quiroga v. Commissioner of Correction, supra, 149 Conn.App. at 174, 87 A.3d 1171. Without knowing the precise basis of the immigration court's ruling, we are left to surmise and speculate as to whether other or additional grounds formed the basis of that court's ruling.
If a petitioner fails to prove that the underlying conviction was the sole basis for his deportation, the appeal also may not be moot if the petitioner can prove collateral consequences by providing "evidence to suggest that, in the absence of the guilty plea, [he] would be allowed to reenter this country or become a citizen." State v. Aquino, supra, 279 Conn. at 298-99 n. 3, 901 A.2d 1194 ; see State v. Chavarro, supra, 130 Conn.App. at 18, 21 A.3d 541 (same); but see St. Juste v. Commissioner of Correction, supra, 155 Conn.App. at 174, 109 A.3d 523 (petitioner must prove both that underlying conviction was exclusive basis for deportation and that petitioner would be permitted reentry in absence of underlying conviction).
*867"[U]nder this court's long-standing mootness jurisprudence ... despite developments during the pendency of an appeal that would otherwise render a claim moot, the court may retain jurisdiction when a litigant shows that there is a reasonable possibility that prejudicial collateral consequences will occur.... [T]o invoke successfully the collateral consequences doctrine, the litigant must show that there is a reasonable possibility that prejudicial collateral consequences will occur. Accordingly, the litigant must establish these consequences by more than mere conjecture, but need not demonstrate that these consequences are more probable than not. This standard provides the necessary limitations on justiciability underlying the mootness doctrine itself. Where there is no direct practical relief available from the reversal of the judgment ... the collateral consequences doctrine acts as a surrogate, calling for a determination whether a decision *444in the case can afford the litigant some practical relief in the future." (Citation omitted; internal quotation marks omitted.) State v. Jerzy G., supra, 162 Conn.App. at 165-66, 130 A.3d 303.
The respondent contends that the petitioner has not and could not establish that he would be allowed reentry into this country because (1) under 8 U.S.C. § 1229b (a) and (d),2 the petitioner would have to establish that *868he had been in this country continuously for more than seven years before his deportation began to be eligible to apply to vacate that order of deportation, and he had lived here, at most, six and one-half years before the relevant statutory time period began, and (2) officers discovered that the petitioner had been growing marijuana in his home and had paraphernalia indicating sale of marijuana, and, although that charge had been nolled in this case as part of the plea deal, the petitioner admitted in open court before the habeas judge that he had been growing marijuana. The respondent contends that pursuant to 8 U.S.C. § 1182(a)(2)(A),3 the petitioner *869could be *445denied readmission because he admitted to drug activity, and pursuant to 8 U.S.C. § 1182(a)(2)(C),4 he could be denied readmission if the Attorney General of the United States has reason to believe he engaged in drug activity. Notwithstanding these federal statutes, the petitioner made no attempt to establish his eligibility for reentry before the habeas court. This failure is fatal to his claim. See Paulino v. Commissioner of Correction, supra, 155 Conn.App. at 164, 109 A.3d 516.
Because we are unable to ascertain the precise basis for the order of deportation issued by the United States *870Immigration Court, and the petitioner failed to produce any evidence before the habeas court that, in the absence of his convictions, he would be permitted to return to the United States, we conclude that this appeal is moot.
The appeal is dismissed.
In this opinion the other judges concurred.