On June 12, 2007, a grand jury indicted the defendant for attempted murder, G. L. c. 265, § 16 (count one); armed home invasion, G. L. c. 265, § 18C (count two); and five related crimes.1 On January 6, 2009, he pleaded guilty to all charges. On count one, the attempted murder charge, the judge imposed a sentence of from five years to five years and one day in State prison. On count two, the armed home invasion charge, she sentenced the defendant to five years’ probation with conditions, to follow the sentence imposed on the attempted murder charge. On the remaining counts, she imposed five-year terms of *531probation, each to run concurrently with the probationary term imposed on count two.

The Commonwealth petitioned for relief in the county court pursuant to G. L. c. 211, § 3, arguing that the sentence imposed on the armed home invasion conviction contravened the provisions of G. L. c. 265, § 18C, as amended through St. 2004, c. 150, § 17 (§ 18C), which the Commonwealth contends does not permit a probationary sentence in lieu of a mandatory minimum twenty-year term of incarceration. A single justice of this court reserved and reported the case without decision to the full court. In light of the successive changes the Legislature has made to § 18C since 1998, we find the statute ambiguous with respect to whether it currently permits a sentence of probation. The rule of lenity, see Commonwealth v. Crosscup, 369 Mass. 228, 234 (1975), therefore comes into play, and we are constrained to conclude that § 18C in its present form does allow a judge to impose a probationary sentence.

The unusual history of the armed home invasion statute directs our decision. The original version of G. L. c. 265, § 18C, inserted by St. 1993, c. 333, consisted of two sentences:

“[1] Whoever knowingly enters the dwelling place of another knowing or having reason to know that one or more persons are present within or knowingly enters the dwelling place of another and remains in such dwelling place knowing or having reason to know that one or more persons are present within while armed with a dangerous weapon, uses force or threatens the imminent use of force upon any person within such dwelling place whether or not injury occurs, or intentionally causes any injury to any person within such dwelling place shall be punished by imprisonment in the state prison for life or for any term of not less than twenty years. [2] The sentence imposed upon a person who, after having been convicted of violating any provision of this section, commits a second or subsequent offense under the provisions of this section shall not be suspended or placed on probation.”

In 1998, the Legislature amended § 18C by inserting, between the statute’s first and second sentence, three sentences concerning the commission of the crime with specified types of firearms *532— thereby converting the original second sentence into the fifth sentence of the statute.2

Following this court’s decision in Commonwealth v. Brown, 431 Mass. 772 (2000),3 and the Appeals Court’s decision in *533Commonwealth v. Berte, 57 Mass. App. Ct. 29 (2003),4 the Legislature amended the statute again in 2004. See St. 2004, c. 150, § 17. The 2004 amendment deleted the second, third, fourth, and fifth sentences of the 1998 version of the section. As a result, § 18C, which has not been amended since 2004, now consists of a single sentence and reads as follows:

“Whoever knowingly enters the dwelling place of another knowing or having reason to know that one or more persons are present within or knowingly enters the dwelling place of another and remains in such dwelling place knowing or having reason to know that one or more persons are present within while armed with a dangerous weapon, uses force or threatens the imminent use of force upon any person within such dwelling place whether or not injury occurs, or intentionally causes any injury to any person within such dwelling place shall be punished by imprisonment in the state prison for Ufe or for any term of not less than twenty years.”

G. L. c. 265, § 18C, as amended through St. 2004, c. 150, § 17. Notably, the 2004 amendment removed all references to proba*534tian in the section, even the one that was in § 18C as originally enacted in 1993. See St. 1993, c. 333.

In Commonwealth v. Hines, 449 Mass. 183 (2007), the court considered a provision concerning probation ineligibility in G. L. c. 265, § 18B, as amended through St. 1998, c. 180, § 56, that is similar to one of the provisions inserted into § 18C in 1998, but deleted in 2004.5 We held that the provision prohibited probation as a disposition for any person convicted under § 18B. Id. at 190-191. See Commonwealth v. Lightfoot, 391 Mass. 718, 721 (1984) (interpreting almost identical language about probation ineligibility in G. L. c. 272, § 7, as amended by St. 1980, c. 409, as precluding defendant from receiving sentence of probation). As the statutes reviewed in these two cases illustrate, when the Legislature intends to bar probation, it knows how to say so explicitly. In this context, the Legislature’s decision in 2004 to remove all language from § 18C that expressly prohibited probation leaves a question in our minds regarding its intent with respect to the availability of a probationary sentence.

The Commonwealth argues that the fact that the current version of § 18C does not contain specific language prohibiting a probationary sentence is not dispositive. It goes on to argue that even if § 18C as originally enacted in 1993 implicitly permitted probation for first-time offenders in the first sentence of the statute by expressly barring probation for subsequent offenders in the second and final sentence, because the Legislature removed that express bar in 2004, the statute should now be read to prohibit a probationary sentence for all offenders.

The Commonwealth is correct that the Legislature “is not restricted to one means of expression” in establishing a sentencing scheme, Commonwealth v. Brown, 431 Mass. at 776, and *535“need not, at its peril, use the exact same formula for each statutory provision in order to achieve a particular result.” Commonwealth v. Vega, 449 Mass. 227, 232-233 (2007). However, while it is possible to read the Legislature’s removal of the final sentence of § 18C to signify, as the Commonwealth suggests, that a disposition of probation is not available to any offender, we cannot say with certainty that the Legislature intended this result. It seems reasonable to assume that the 2004 amendment was in some respects a response to the invitations in Commonwealth v. Brown, supra at 780-781, and Commonwealth v. Berte, 57 Mass. App. Ct. at 34, to clarify the 1998 amendment. (See notes 3 & 4, supra.) As the defendant suggests, the removal of three explicit prohibitions against probationary sentences for specific categories of offenders may indicate a legislative intent to give a sentencing judge the power, in appropriate situations, to impose a term of probation in lieu of incarceration. “[A]mbiguity concerning the ambit of criminal statutes should be resolved in favor of lenity.” Commonwealth v. Crosscup, 369 Mass. 228, 234 (1975), quoting Rewis v. United States, 401 U.S. 808, 812 (1971). See Commonwealth v. Donovan, 395 Mass. 20, 29 (1985). See also Commonwealth v. Burton, 450 Mass. 55, 59-60 (2007). Therefore, we hold that G. L. c. 265, § 18C, as amended through St. 2004, c. 150, § 17, does not prohibit a judge from sentencing the defendant to probation.

We recognize that this result, which has the effect of offering a sentencing judge a choice between probation and a mandatory minimum prison term of twenty years,6 may seem contrary to common sense. Standing alone, the statutory language in the first sentence of § 18C, “shall be punished by imprisonment . . . for life or for any term of not less than twenty years,” would suggest a legislative intent that a defendant convicted under the statute could be sentenced to only a term of incarceration, not probation. However, we must read this language in the context of the 1998 and 2004 amendments, and for the reasons we have discussed, they render ambiguous what might otherwise be clear.7 *536Cf. Commonwealth v. Roucoulet, 413 Mass. 647, 652-653 (1992).

Section 18C has caused confusion in the past with respect to the penalty portion of the statute, and this is not the first time that such confusion has yielded what may appear to be an anomalous result. See Commonwealth v. Burton, 450 Mass. at 60 (reducing conviction of felony-murder in first degree to felony-murder in second degree because armed home invasion not punishable by life imprisonment under 1998 version of § 18C).* **8 We again invite the Legislature to clarify G. L. c. 265, § 18C.

The case is remanded to the county court for the entry of a judgment dismissing the Commonwealth’s petition under G. L. c. 211, § 3.

So ordered.