The most recent update information in the GPO database says:
GPO server down, busy, or producing abnormal result
and is the best information about currency we can obtain from the GPO system;
it may not be very helpful.
There may be a more up-to-date version of this section at the GPO. You may also get a list of bills that mention this section from the Thomas system at the Library of Congress.
For a number of reasons you may want to check for updates manually. It is possible that the GPO server is down or busy, or that the update service offered by GPO is itself out of date.
UPDATING A SECTION MANUALLY
To determine if particular section has been amended you need to inspect the so-called "classification tables" prepared by the Office of the Law Revision Counsel of the House of Representatives. These map recently-passed laws and amendments to the Code to the particular sections of the Code that are affected. You can find them at the House server. Using the title and section of the Code that you are interested in, look through the tables sorted by Code section. Write down any of the Public Law numbers that affect the section you are interested in.
USING THE UPDATE RESULTS WITH THE LIBRARY OF CONGRESS DATABASE
Using the Public Law number(s), you can use the Library of Congress database (Thomas) to retrieve and read the actual text of the amendments. To do this, go to the Thomas database and click on the link labelled "public laws". Pick the Congress you're interested in -- this will be the number to the left of the hyphen in the Public Law number (for example, PL 108-123 is the 123rd law passed by the 108th Congress). You can then use the Thomas system to navigate to the particular law you are interested in.