Any company incorporated under the laws of this state prior to April eighth, one thousand nine hundred and twenty-one, and engaged in supplying gas for public or private use in a municipality in this state having a population of less than fifteen thousand, may extend, renew and continue its corporate existence and powers in the manner provided in this article.
This article shall apply to any company whose charter may have expired prior to the filing of the certificate mentioned in section 48:9-27 of this title provided the certificate is filed within four months after the expiration of the charter.