datetime: Undefined function 'datetime' for input arguments of type 'double'

I am using following code to convert datenum to datetime

x=723707;
y=datetime(x,'ConvertFrom','datenum');

I get the error message:

 Undefined function 'datetime' for input arguments of type 'double'.

When I try

 open datetime

I get the error message that

 file 'datetime' does not exist.

I don't understand what's wrong. Please help. I am using MATLAB 2014a.

Answer 1

[Walter Roberson]

datetime() was introduced in R2014b.

[Abhinav]

Oh. I apologize. I looked at the release version in 'datetime' argument and misread it for 2004.