OPINION
C. JOHNSON, Judge.1 On November 19, 2009, Appellee, Den-zel Dean Salathiel, pled guilty to Actual Physical Control of a Motor Vehicle While Under the Influence of Intoxicants, a misdemeanor (47 O.S8.Supp.2006, § 11-902(A), (C)(1)) in Oklahoma County District Court Case No. CM-2008-4007.1 Pursuant to the plea agreement, and as permitted by 22 0.S.8upp.2005, § 991¢, the court deferred imposition of judgment for two years, subject to Appellee's successful compliance with standard conditions of probation. Appellee completed the two-year probationary period without incident, and the case was subsequently dismissed.
T2 On February 22, 2012, Appellee was arrested in Oklahoma County for Driving Under the Influence of Intoxicants (47 O.S. 2011, § 11-902(A), (C)(2)), and he was formally charged on March 28, 2012 in Oklahoma County District Court Case No. CF-2012-1892. To elevate this crime from a misdemeanor to a felony, the State alleged that Appellee had previously committed a violation of § 11-902, as charged in CM-2008-4007.2 Appellee filed a Demurrer and Motion to Dismiss, alleging that the State could not lawfully enhance the 2012 DUI charge with his plea in CM-2008-4007, be*265cause Appellee had successfully completed the terms of the deferred judgment in that case. The State filed a brief in response. On June 19, 2012, the Honorable Larry Jones, Special Judge, sustained Appellee's motion. The State appealed that ruling to the district court pursuant to 22 0.98.2011, § 1089.1 et seq. On July 10, 2012, the Honorable Glenn M. Jones, District Judge, affirmed the magistrate's ruling. The State now appeals the district court's ruling to this Court, pursuant to 22 0.8.2011, § 1089.7. The case was automatically assigned to our Accelerated Docket. Rule 11.2(A), Rules of the Oklahoma Court of Criminal Appeals, 22 O.S., Ch. 18, App. (2012). Oral argument was held February 14, 2013.
T3 This appeal requires us to interpret language in 47 O.S. § 11-902, Oklahoma's Driving Under the Influence (or "DUI") statute-specifically, changes to the statute which took effect November 1, 2011, between the time of Appellee's two prosecutions thereunder. At all times relevant to Appel-lee's first prosecution in 2008-09, a first DUI offense was a misdemeanor; a person faced felony punishment only if he had been "con-viected" of a DUI offense within the ten years preceding the commission of the new offense. 47 0.8.Supp.2006, § 11-902(C)(@). The 2011 amendment, however, permits felony enhancement not only with a prior conviction for a DUI offense, but also with any prior plea of guilty or nolo contendere to such offense, even if the plea never resulted in a judgment:
Any person who, during the period of any court-imposed probationary term or within ten (10) years of the date following the completion of the execution of any sentence or deferred judgment for a violation of this section or a violation pursuant to the provisions of any law of this state or another state prohibiting the offenses provided in subsection A of this section, ... commits a second offense pursuant to the provisions of this section or has a prior conviction in a municipal criminal court of record for the violation of a municipal ordinance prohibiting the offense provided for in subsection A of this section and within ten (10) years of the date following the completion of the execution of such sentence or deferred judgment commits a see-ond offense pursuant to the provisions of this section shall, upon conviction, be guilty of a felony ...
47 0.8.2011, § 11-902(C)(2) (emphasis added). The 2011 amendment also added a new paragraph, which underscores the change:
Any plea of guilty, nolo contendere or finding of guilt for a violation of this section or a violation pursuant to the provisions of any law of this state or another state prohibiting the offenses provided for in subsection A of this section, Section 11-904 of this title, or paragraph 4 of subsection A of Section 852.1 of Title 21 of the Oklahoma Statutes, shall constitute a conviction of the offense for the purpose of this section for a period of ten (10) years following the completion of any court-imposed probationary term.
47 00.98.2011, § 11-902(M) (emphasis added)3
14 As stated above, Appellee's 2009 plea was entered as part of a deferred-judgment agreement, authorized by 22 O.8. § 991c. In 1970, the Oklahoma Legislature created this procedure whereby the court could "defer" the rendition of judgment in a criminal case for a period of time. Typically, a judgment is deferred in exchange for the defendant's plea of guilty or nolo contendere, and his agreement to abide by certain conditions for a specified period of time. Unlike the district court's authority to suspend execution of a sentence, see 22 0.8.2011, § 9912, where judgment of guilt is rendered but the execution of the sentence is "suspended" in whole or in part, on conditions of probation, under a deferred-judgment procedure no judgment of guilt is rendered unless and until the defendant violates the terms of the agreement.
15 Although the statute has been amended several times over the years, the *266basic mechanics of § 991c have remained unchanged:
Upon a verdict or plea of guilty or upon a plea of nolo contendere, but before a judgment of guilt, the court may, without entering a judgment of gwilt and with the consent of the defendant, defer further proceedings upon the specific conditions prescribed by the court not to exceed a five-year period....
Upon completion of the conditions of the deferred judgment, ... the defendant shall be discharged without a court judgment of guilt, and the court shall order the verdict or plea of guilty or plea of nolo contendere to be expunged from the record and the charge shall be dismissed with prejudice to any further action ....
22 0.8.Supp.2005, § 99le(A), (C)4 If the defendant violates any condition to the deferred judgment procedure, the court may proceed to enter judgment of guilt (which, in cases involving a previously-tendered guilty or nolo plea, requires the court to first "accept" that plea) 22 O.8.Supp.2005, § 991c(E). On the other hand, a defendant who successfully completes the terms of the deferred-judgment agreement is entitled, by operation of law, to have the entire proceeding-including any tendered guilty plea-expunged from the record. 22 0.S$.Supp.2005, § 991e(C). Moreover, such expungement is expressly declared by the Legislature to have retroactive effect. 22 0.8.8upp.2005, § 991e(D).
T 6 The 2011 amendments to the DUI statute, 47 0.8. § 11-902, prompted the State to seek enhanced punishment for Appellee's 2012 DUI prosecution, using his guilty plea to a DUI offense in November 2009. In the State's view, the fact that Appellee had sue-cessfully completed his part of the deferred-judgment agreement in the prior case was made irrelevant by the intervening changes in the DUI law. Appellee challenged this interpretation under several theories. First, he argued that treating his 2009 guilty plea as tantamount to a "conviction" violated a basic rule of statutory construction, i.e., that statutes should not be given retroactive effect unless their language expressly declares otherwise. Alternatively, Appellee argued that application of the 2011 amendment, to a guilty plea made in 2009, would violate his constitutional guarantees against ex post fac-to laws, bills of attainder, and impairments to his ability to contract. See Okla. Const. Art. 2, § 15 ("No bill of attainder, ex post facto law, nor any law impairing the obligation of contracts, shall ever be passed").
T7 Both the examining magistrate and the district judge agreed that the State should not be allowed to use Appellee's prior guilty plea for enhancement. In its written order, the district court concluded that doing so would constitute an ex post facto violation, as it "increase[s] statutory punishment for the crime, [and] changes the collateral consequence[s] of the defendant's plea and deferred judgment which he expected pursuant to statutes then in existence." (O.R. 48) We review the district court's ruling for an abuse of discretion. State v. Swicegood, 1990 OK CR 48, ¶7, 795 P.2d 527, 529. While we agree with the tenor of the district court's reasoning, we reach the same conclusion it did using a slightly different legal rationale.
18 It is a fundamental rule of statutory construction that intervening changes in the law should only be applied prospectively from their effective date, unless the Legislature has specifically declared that they have retroactive effect. Nestell v. State, 1998 OK CR 6, ¶5, 954 P.2d 143, 144; State v. Watkins, 1992 OK CR 50, ¶5, 837 P.2d 477, 478. The common-law presumption against retroactive application of statutes, and the constitutional proscriptions against ex post facto laws, bills of attainder, and impairments of contract, are all variations on a common theme in our law. They balance the Legislature's authority to enact laws with the ideas of adequate notice, reasonable reliance, and fair play.
T 9 Below and on appeal, the State correctly observes that the 2011 amendment to § 11-902 does not purport to eriminalize con*267duct committed before its enactment. In other words, the State is not attempting to re-prosecute Appellee, or to punish him any further, for any DUI offense in 2008. Rather, the 2011 amendments re-define what kind of evidence can be used to enhance punishment for a new offense. It might be said that after November 1, 2011 (the effective date of the amendment), anyone who gets behind the wheel, while under the influence of intoxicants, is on notice that his guilty plea to a past DUI offense could be used to enhance punishment-even if no judgment of guilt had ever been entered and the matter had been expunged. In that sense, certainly, the changes to the statute have prospective effect.
110 However, "(al law is retroactive if it changes the legal consequences of acts completed before its effective date." Miller v. Florida, 482 U.S. 423, 430, 107 S.Ct., 2446, 2451, 96 L.Ed.2d 351 (1987) (citations omitted). By re-defining what counts as a "conviction" for purposes of enhancing a DUI offense to a felony, the amendment to § 11-902 changes the legal effect of conduct undertaken by the parties (the State and the defendant) at some time in the past. Before the amendment, any defendant who pled guilty or nolo contendere to a misdemeanor DUI offense, pursuant to a deferred-judgment agreement, could reasonably rely on the promise of 22 0.8. § 991e: that his sue-cessful compliance with the agreement would, in effect, erase the matter from his record. Clearly, any defendant in that position today, after the effective date of the amendment to 47 0.8. § 11-902, would be on notice that the matter might be used against him anyway, were he to commit another such offense within ten years. But before November 2011, that potential outcome would have been completely contrary to the parties' understanding of a deferred-judgment plea agreement in a misdemeanor DUI case.
T11 The United States Supreme Court addressed a similar situation in I.N.S. v. St. Cyr, 533 U.S. 289, 121 S.Ct. 2271, 150 L.Ed.2d 347 (2001). In that case, the respondent, a Haitian citizen with permanent-resident status in the United States, pled guilty in state court to a drug offense. Although the resulting conviction made him deportable under federal immigration law, at the time the law also gave the United States Attorney General the discretion to waive deportation in the respondent's cireumstances. After the respondent entered his plea, Congress enacted new laws which removed the Attorney General's authority to grant such waivers. The respondent argued that it was unfair to apply that change in immigration law retrospectively, to aliens who had pled guilty in reliance on the law as it existed at the time of their pleas.
1 12 The federal district court agreed with the respondent. So did the court of appeals. And ultimately, the Supreme Court did too. The Court observed that "[rletroactive statutes raise special concerns," because of the government's "unmatched powers ... to sweep away settled expectations." Id., 588 U.S. at 815, 121 S.Ct. at 2287. Consequently, a presumption against retroactive application of statutes is "deeply rooted in our jurisprudence, and embodies a legal doctrine centuries older than our Republic." 588 U.S. at 316, 121 S.Ct. at 2288. Because of this presumption, the Court said, a statute may not be applied retroactively "absent a clear indication from Congress that it intended such a result." Id. The standard for finding such a clear indication is "a demanding one"; the Court observed that in past cases where retroactive application was countenanced, the statutory language was "so clear that it could sustain only one interpretation." 588 U.S. at 816-17, 121 S.Ct. at 2288.
1138 After a careful examination of the laws in question, see 533 U.S. at 817-820, 121 S.Ct. at 2288-2290, the Supreme Court found no express indication that Congress intended retroactive effect of the provision at issue. The Court then considered the more fundamental question: whether the statute actually did operate retroactively at all. Whether a statute operates retroactively, the Court held, "demands a commonsense, functional judgment about whether the new provision attaches new legal consequences to events completed before its enactment." 533 U.S. at 821, 121 S.Ct. at 2290 (quotation and citation omitted). "[Wlhether a particular statute acts retroactively should be informed *268and guided by familiar considerations of fair notice, reasonable reliance, and settled expectations." 588 U.S. at 321, 121 S.Ct. at 2291 (quotation and citations omitted).
*% 14 The fact that St. Cyr involved a plea of guilty was important to the result. "Plea agreements involve a guid pro quo between a criminal defendant and the government," the Court observed, where the defendant waives constitutional rights and grants the government tangible benefits, such as avoiding the effort and expense of a trial. 588 U.S. at 821-22, 121 S.Ct. at 2291. The Court found historical evidence for concluding that "alien defendants considering whether to enter into a plea agreement [were] acutely aware of the immigration consequences of their convictions," and indeed, that the alien defendant's right to remain in the United States "may be more important [to him] than any potential jail sentence." 583 U.S. at 822-23, 121 S.Ct. at 2291 (quotation and citation omitted). Retroactive application of the change in federal immigration law would have removed a tangible benefit that Mr. St. Cyr undoubtedly relied upon in deciding to enter a plea in the first place. 533 U.S. at 825, 121 S.Ct. at 2298. The Court refused to read the new law to allow such a result, absent clear legislative intent to the contrary. 583 U.S. at 826, 121 S.Ct. at 2298.
115 Like St. Cyr, the case before us involves a defendant who pled guilty to a crime based on a certain understanding of the possible outcomes-outcomes that were subsequently altered by operation of law. We find nothing in the 2011 amendment to 47 0.8. § 11-902 which clearly declares that the enhancement language at issue here shall have retrospective effect. We therefore conclude that the amendment's re-definition of what constitutes a prior DUI "conviction" applies only to pleas of guilty or nolo contem-dere entered after the effective date of the 2011 amendment itself. Having reviewed the thorough analyses conducted by both the examining magistrate and the district judge, we find no abuse of discretion therein. Because we base our conclusion on rules of statutory construction, we need not decide, at this time, whether the amendments in question would violate constitutional guarantees against ex post facto laws, bills of attainder, or impairments to the obligations of contracts. See Reimers v. State ex rel. Dept. of Corrections, 2011 OK CIV APP 83, ¶¶29-32, 257 P.3d 416, 420-21.
DECISION
116 The district court's order affirming the magistrate's ruling is AFFIRMED. Pursuant to Rule 3.15, Rules of the Oklahoma Court of Criminal Appeals, Title 22, Ch.18, App. (2013), the MANDATE is ORDERED issued upon the delivery and filing of this decision.
LEWIS, P.J.: dissent. SMITH, V.P.J. and A. JOHNSON, J.; concur. LUMPKIN, J.: specially concur.. The offense was alleged to have occurred on or about September 17, 2008.
. The statute in question equally punishes those who "drive, operate, or [are] in actual physical control of a motor vehicle" on designated roadways in the State while they are under the influence of intoxicants (or, alternatively, while having a specified concentration of alcohol in their blood or breath). A person may thus be convicted of "APC" (Actual Physical Control) instead of "DUI" (Driving Under the Influence) if he was intoxicated and behind the wheel of an operable motor vehicle, even if the vehicle was not in motion; but the two crimes are interchangeable for our purposes here, as a prior conviction for one can be used to enhance punishment for the other. See generally 47 O.$.Supp.2011, § 11-902. In this opinion, the term "DUI" or "DUI offense" is used as a generic label for a prosecution under this statute, regardless of theory.
. The 2011 amendment also extended the ten-year viability period for a prior DUI offense, from ten years after the date of the prior conviction, to ten years after completion of any sentence or probation received for same. Compare 47 O.S.Supd.2009. § 11-902(C)(2) with 47 O.S. 2011, § 11-902(C)(2), (M). That change has no bearing on our disposition of this case, however.
. Although § 991c has been amended since Ap-pellee's 2009 deferred judgment, those changes have no bearing on the issues presented here.