How do we edit xticks datetime format?

I am trying to increase the number of date tick marks on a graph,

but I cannot change the resulting datetime format:

Code that I think ought to work to obtain this result doesn't. I have tried the following (with a different initial datetime):

 xticks(linspace(datetime('1234-11-06'),datetime('2067-04-25'),6))
 xticks(linspace(datetime('06-Nov-1234','Format','yyyy-MM-dd'),datetime('25-Apr-2067','Format','yyyy-MM-dd'),5))
 xticks(linspace(datetime('1234','InputFormat','y','Format','y'),datetime('2067','InputFormat','y','Format','y'),8))
 xticks(linspace(datetime('1234','InputFormat','y','Format','yyyy-MM-dd'),datetime('2067','InputFormat','y','Format','yyyy-MM-dd'),8))

What is the problem? How do I increase the number of dates?

[Steven Lord]

Which release are you using?

How did you create the plot? Did you plot with numeric or datetime X data? It can make a difference.