Release 2.9.0 introduces DF basis generator, increases max L for exponential integrals, and several misc improvements.
In addition to citing Libint2 as explained in file CITATION, please cite 
What's Changed
- AM symbols list by @loriab in #325
- narrow down the distribution of cartesian coordinates of shells produced by RandomShellSet by @evaleev in #327
- increase tenno function interpolation table to support m<=36 by @evaleev in #329
- add soversion to lone shared lib by @loriab in #331
- can use modularized Boost, even if built as part of the main project by @evaleev in #333
- bump Catch2 to 2.13.10, resolves #328 by @evaleev in #334
- Automatic Density Fitting basis generator by @kshitij-05 in #281
- l->symbol maps condensed to 1 definition for non-Python code by @evaleev in #335
New Contributors
- @kshitij-05 made their first contribution in #281
Full Changelog: v2.8.2...v2.9.0
Contributors
evaleev, loriab, and kshitij-05