Getting an older version of a package

Hi there,

Thanks for your time in advance.

I am using an add-on package from Cran. After I updated this package,
some of my programs don't work any more. I was wondering if there is
anything like version control so that I could use the older version of
that package; or if I could manually install the previous version and
how I could acheive it? I am not a regular R user; although it is
supposed to be very easy, after spending many hours on this, I still
haven't figured out how to proceed. Your help will be greatly
appreciated.

Thanks.
Le

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Le Wang, Ph.D
Population Center
University of Minnesota