Colorado school districts looking to bolster security are planning to spend millions of dollars upgrading locks on classroom doors.

The Denver Post says the districts need the equipment retrofits to comply with an updated Colorado Division of Fire and Prevention Control code requirement that that calls for public, charter and junior colleges to have locks in designated classrooms that can be locked from the inside.

According to the revised regulation, non-compliant locks must be removed by Jan. 1, 2018.

The Denver district has scheduled a $572 million bond election for November and has earmarked $4 million for classroom door locks that enable students and teachers to secure a room without having to go into the corridor. District officials say the planned upgrades are less about the fire code requirement and more of a proactive desire to enhance the safety of students and staff.

Elsewhere in Colorado, the Jefferson County district is estimating a nearly $5 million price tag to replace the locks in its classrooms. Adams 12 Five Star Schools is planning to spend up to $3 million on new locks.