raised the point that we seem to have no written guidelines for dealing with copyright dates in the headers of our source code. It's been part of institutional memory, but we need to capture it somewhere, and the official developer guide seems the right place.

Briefly, here's the deal.

Every source code file in our code bases (whether it's for OpenNMS or another project) should have a comment block at the top which includes copyright information, followed by a license portion. The copyright portion looks like this for a Java source file that is part of the main OpenNMS code base:

The two lines containing copyright dates are the focus of this issue.

The first line is specific to the file at hand. The second line applies to the code base as a larger work. One or both lines may need updating any time a developer makes changes to a file. For purposes of identification in the matrix below, I'll assign identifiers [in brackets] to the four years as follows:

Here's an attempt at a matrix illustrating what should change in various scenarios. It assumes that the developer is updating the file in the year 2022 (Gregorian calendar).

If Year B or Year D is empty, its companion year (A or C) should not be followed by a dash.

I hope this is enough to make a start. Please tag me with any questions!