¶1The defendants do not contend, and we think they could not successfully contend, that the security to be furnished upon an appeal under the Pub. Sts. c. 175, § 6, in a suit to recover possession of land should be by recognizance, and not by bond. See Granger v. Parker, 142 Mass. 186; St. 1882, c. 95.
¶2The condition of the bond in this case differs in its language from that called for by the statute. A defendant, upon taking an appeal in a case of this kind, should bind himself “ to enter the action, and to pay to the plaintiff if the final judgment is in his favor all rent then due, all intervening rent, and all damage and loss which he may sustain by reason of the withholding of the possession of the demanded premises, and by reason of any injury done thereto during such withholding, together with all costs until the delivery of the possession thereof to him.” Pub. Sts. c. 175, § 6. The condition of this bond is to “ enter and prosecute his said appeal at said Superior Court with effect, and satisfy any judgment which may be entered against him in said Superior Court, and all rent due or to become due, damages, and costs upon said appeal, and for costs within thirty days of the entry of such judgment.”
¶3If this were not a bond, but a recognizance, which would be void for want of jurisdiction in the magistrate if it purported to secure performance of more than the recognizor could lawfully be required to do, we should hesitate to declare it invalid by *328reason of its departure from the language of the statute. A change of form not affecting the substance of the condition would not render it so. Martin v. Campbell, 120 Mass. 126. Nor a failure to include in the statement of the obligation all that the statute prescribes. Shaw v. McIntier, 5 Allen, 423. And it is difficult to see what greater obligation as to rent, damages, or costs is stated in the bond, than is described in the statute which we have quoted.
¶4But it is unnecessary to decide whether the contract is valid under the statutes, for, if not, it is binding at common law. It was entered into voluntarily, it contains nothing in conflict with the statute, and it is not otherwise illegal. Obligors who sign such an instrument are bound by it. Morse v. Hodsdon, 5 Mass. 314. Sweetser v. Hay, 2 Gray, 49. Bank of Brighton v. Smith, 5 Allen, 413. Conant v. Newton, 126 Mass. 105.
¶5The date of the bond does not affect its validity. The paper upon its face shows an error in date; for it is dated August 13, and it recites proceedings in court as having occurred August 16. But it took effect when it was filed and approved, and the mistake created no ambiguity, and was not misleading. Battles v. Fobes, 21 Pick 239. Shaughnessey v. Lewis, 130 Mass. 355.
¶6The presiding judge correctly ruled, that, if the mother of the defendant in the original suit occupied the premises described in the writ under an arrangement with him that she should have them in exchange for other premises which she gave up to him, that might be regarded by the jury as his occupation. The ruling as to the description of the premises was also correct.
¶7Neither the principal defendant nor his sureties, after having given this bond as a means of obtaining an appeal which has been prosecuted to final-judgment without objection, can now be permitted to dispute the validity of that judgment on account of the difference which appears between the language of the bond and that prescribed by the statute. Fall River v. Riley, 140 Mass. 488. Granger v. Parker, 142 Mass. 186.
¶8The only remaining question is whether the plaintiff was entitled to rent after the expiration of his first lease, while his title and right of possession continued under a second lease which took effect from the expiration of the first. It does not appear how this could have affected the rights of either party at the *329trial of the question of liability; for upon showing a breach of the bond in any particular, the verdict and judgment should have been for the penal sum named in it, and the amount for which execution was to be awarded should have been ascertained in a subsequent proceeding. Pub. Sts. c. 171, §§ 9, 10.
¶9In determining that, the rental value of the premises was to be considered up to the time when the plaintiff obtained possession under his execution. It is unnecessary to determine what would have been the effect as to judgment and execution in the original suit if the plaintiff had not taken his second lease, and if the expiration of the first had been pleaded while the suit was pending. His right to recover when he commenced his action was established, and that entitled him to judgment and execution. In the absence of anything to show a change, his right continued under the new lease, and judgment and execution followed. A fair construction of the language of the bond, “ all rent due and to become due,” includes rent during the term of the second lease, as well as of the first.
¶10Exceptions overruled.