Colo. Rev. Stat. § 31-25-1106
The notice required by section 31-25-1105 shall be published twice in a newspaper of general circulation in the county in which the proceeding is instituted. The fact of such publication shall be conclusively established by the publisher's affidavit of publication. The first publication of such notice shall be more than ten days and the last publication within five days before the date set for the hearing. In addition to such published notice, the clerk of the court shall mail a copy of such notice to each record owner of the property described in such notice and to every mortgagee, lien claimant, or other person having any right, title, or interest in or to said property as disclosed by the records on file in the office of the county clerk and recorder of the particular county. Copies of such notice shall be sent to such owners and persons at their last-known addresses. If addresses of such owners and persons are unknown to the clerk, notices shall be directed to the post office nearest to the property described in said notice. Also, the clerk of the district court shall cause a copy of the notice to be served on some person occupying the property described in such notice, if there are any. The mailing and serving of notices shall be completed at least ten days before the date of the hearing specified in the notice. Affidavit thereof shall be filed in the clerk's office, which affidavit shall be prima facie evidence of the fact of such mailing and service.
C.R.S. § 31-25-1106