I have three GeoPackage-related updates for you. First of all, the GeoPackage SWG has wrapped up its work on the Tiled, Gridded Coverage Extension (formerly the elevation extension). Look for OGC to make a press release soon. There will be an open comment period followed by an adoption vote (probably electronic) by the OGC Technical Committee. Of course if you have any comments, you do not have to wait until the press release. You can go directly to the GitHub repository and open an issue from there.
Second, you may have noticed a slight change to the geopackage.org page. We now have separate links to the adopted version of the standard and the working version on the top right. We have made a few administrative changes that we want to get into the public eye even though they are not yet part of an approved document. These are now incorporated to the working version which is tentatively titled 1.3_SNAPSHOT.
There is a third development that will affect the standard, though it should not directly affect implementers. OGC is developing a Tile Matrix Set Encoding Standard. This document extracts the TileMatrixSet definition from Web Map Tile Service (WMTS) and makes it a independent document designed to be referenced by other standards such as GeoPackage. If OGC adopts this standard, we will update the GeoPackage standard to bring them into alignment. I don't have a timeline for any of this, but whenever this work is complete we will probably release it as GeoPackage 1.3.
 For a recap of this topic, see paragraphs 2 and 3 of http://geopackage.blogspot.com/2017/05/good-news-bad-news.html
 See https://github.com/opengeospatial/geopackage/pull/387, https://github.com/opengeospatial/geopackage/pull/392, and https://github.com/opengeospatial/geopackage/pull/394
 The working version of this draft standard, available to OGC members, is here: https://portal.opengeospatial.org/files/?artifact_id=76617.