Verified answer

Both are CMOS devices. CD4067 is slower device compared with 74HC4067. HC stands for High Speed CMOS. CD4067 has maximum ON/OFF time of 190/130 nS where as 74HC4067 has maximum ON/OFF time of 64/62 nS. CD4067 is older device in comparison with 74HC4067.

The CD4000 series is MOS, and the 74HC4000 series is mil. spec. CMOS. CMOS is much more durable and reliable in terms of voltage, noise, and electrostatic discharge than MOS. Schematically, the circuits appear identical, with the only difference being the "beefing up" of the CMOS.

(MOS is metal oxide semiconductor, and CMOS is complimentary metal oxide semiconductor.)

If you are replacing a CD74HC4067 you can use either a CD74HC4067 or a CD54HC4067. Unfortunately, I don't think you can "upgrade" from a CD4067 due to external circuit design, although it's been a long time, and I may be wrong on this.

Cd4067

Oh.. brb.