Any portal Administrator will be able to upload new documents and manage existing documents. Each document can be linked to a version. In addition, each document can have a start date and an expiry date.
As an example, if you have a number of SOPs which are valid until the end of 2015, you can set the expiry date to Dec 31, 2015. From Jan 01, 2015, such a document will no longer be listed. And if you have a newer version of a SOP which is valid from Jan 01, 2016, you can upload this document anywhere before this date and set the 'Start date' to Jan 01, 2016.
For each document, you can set a revision date. This allows to select all documents (SOPs) which require a revision.