I try to submit an article with citations to arxiv.org, and the TeX output says

Package biblatex Warning: File 'main.bbl' is wrong format version - expected 2.8.

Okay, so my local biblatex/biber combination is incompatible with arxiv's. Can anyone tell me which biblatex/biber combination produces BBL format 2.8?

  • 1
    biblatex 3.8 corresponds to biber 2.8 (See the 'biber/biblatex compatibility matrix' in the biblatex documentation) – leandriis Feb 16 '18 at 18:52
  • Does this produce BBL format 2.8? Because biber version and bbl format are not tied to one another. – Nico Schlömer Feb 16 '18 at 18:53
  • 1
    I am not sure but to me they always seemed to be corresponding. Nevertheless, you might find some useful information regarding the usage of biber/biblatex and arxiv here: tex.stackexchange.com/a/358920/134144 – leandriis Feb 16 '18 at 19:20

If you are looking for help with biblatex and Biber for arXiv uploads, have a look at https://github.com/plk/biblatex/wiki/biblatex-and-the-arXiv

In general, the .bbl file version need not correspond to either the biblatex or the Biber version. The same goes for the .bcf version. The .bbl and .bcf versions can be stepped up with a biblatex/Biber release, but they need not be. In practice that means that the versions trail behind the biblatex/Biber versions and there is only an approximate correspondence between them and the actual package versions.

biblatex 3.5, 3.6 and 3.7 all need .bbl format version 2.8. The corresponding Biber versions are 2.6 (for biblatex 3.5 and 3.6) and 2.7 (for biblatex 3.7). biblatex 3.4 needs .bbl version 2.7, biblatex 3.8 has .bbl version 2.9.

So the newest combination that works with .bbl 2.8 is biblatex 3.7/Biber 2.7. As far as I know that is indeed the version arXiv is using after the February 2017 update Biblatex and arxiv, error.

You can find historic releases of biblatex and Biber at GitHub (https://github.com/plk/biblatex/releases, https://github.com/plk/biber/releases) and SourceForge (https://sourceforge.net/projects/biblatex/files/, https://sourceforge.net/projects/biblatex-biber/files/biblatex-biber/).


I managed to workaround the problem doing the following:

  1. Upload the Latex project in overleaf.
  2. Compile your project in Overleaf.
  3. In the view window, go to the option "Other logs & Files" and download the ".bbl" file. At this time, when I checked the ".bbl" file of Overleaf, it is exactly the version 2.8 of Biblatex.
  4. Rename the "output.bbl" (that you've go from compilation in Overleaf) to the same filename of the ".tex" file which you want to submit to Arxiv.
  5. Upload ".tex", ".bbl" and other supporting files (figures and ".cls") to Arxiv.

It should work now, at least it has worked for me. Thus, this workaround can avoid local installing old versions of Latex and biblate in your computer.

  • Could you please explain in detail your answer? – Raaja May 7 at 14:18
  • Because, what if overleaf decided to do something with their version, would this answer still apply? – Raaja May 7 at 14:24

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