We used to offer all extracts for download in the .osm.pbf and .osm.bz2 data formats. Both formats contain exactly the same information, it is just encoded differently.
The .osm.pbf data format is based on Google's Protocol Buffers. It is on average 40% smaller than the corresponding .osm.bz2 file, and therefore faster to download. It is also faster to process because the .osm.bz2 must be decompressed (at least in memory) to huge XML files before it can be parsed.
Almost all programs that consume OSM data can already read the .osm.pbf data format directly, so there is hardly any need for the .osm.bz2 files any more.
The .osm.bz2 files on our download server have last been updated on 31st December 2024, and will not receive further updates. They are still listed on the web site but these listings will go away in mid-2025, and by the end of 2025 we will completely stop serving them.
If you definitely require .osm.bz2 files, you can use the free software utilities "osmium" (comes with most Linux distributions in a package named "osmium-tool") or "osmosis" (a Java program that is available on all platforms) to convert an .osm.pbf file to an .osm.bz2 file like so:
osmosis --read-pbf myfile.osm.pbf --write-xml myfile.osm.bz2
or
osmium cat myfile.osm.pbf -o myfile.osm.bz2