We're currently offering 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.pbf files are always published earlier than the corresponding .osm.bz2 files, and we have already reduced the update frequency of the .osm.bz2 files because they are CPU intensive to produce - they are only updated every three to five days, whereas the .osm.pbf files are published daily.
We will further reduce the update frequency for .osm.bz2 files throughout the year 2024, and finally stop providing new .osm.bz2 files at the end of 2024.
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
osmium cat myfile.osm.pbf -o myfile.osm.bz2
Even today, this process will give you faster and more current downloads.