Minimum voltage supply for NE555

What is the bare minimum voltage that can be supplied to a NE555 timer to run properly ?

I would like to use 555 to an application where there is only 4.5v available from 3 x 1.5v batteries.

Data sheet says 4.5 is minimum supply voltage.

There are two varieties of 555 timer IC, the regular sort and the cmos sort. The corresponding datasheets specify minimum and maximum supply voltages.

Use the CMOS sort, the ICM7555 or similar, it has a wider supply range, takes less current and needs far less decoupling than a 555 (which really needs 100uF to behave nicely)