support creation of sparklines when exporting Excel tables (#7333)
support sqlalchemy/pandas backed write_database (#7322)
add adbc database reader and writer (DataFrame.write_database) (#7318)
make expr.apply streamable in selection context (#7316)
More ergonomic unnest args (#7310)
initial working version of Decimal Series (#7220)
Support explicit Binary dtype in constructor (#7305)
implement serde for literal datetime and series (#7301)
improve error message if mmap fails in ipc (#7300)
add multi-threaded apply (#7277)
add support for serializing categoricals to json (#7276)
Add Expr.arg_true (#7056)
don't require pyarrow for initialising Series with Python datetimes (#7273)
Excel export support via new write_excel IO method (#7251)
deprecate describe_(optimized)_plan in favor of explain (#7264)
enable min-max skipping for binary in parquet, enable min-max skipping for is_in exprs (#7169)
out of core sort on multiple columns (#7244)
support nulls_last for multi-column sort (#7242)
allow optimizations flags in describe_plan (#7233)
implement row encoding for boolean and binary (#7218)
allow passing utc=True when parsing time-zone-naive date strings (#7203)
Add **named_exprs input for struct (#7208)
add sql "ARRAY_AGG" (#7204)

🐞 Bug fixes

fix offset in threading apply (#7330)
fix projection pushdown on join with unused join key (#7326)
raise error on time -> datetime cast (#7325)
raise error if output of 'apply' cannot be determined (#7317)
make pl.struct mappable (#7299)
err on duplicate with_column names (#7296)
don't panic on str.parse_int (#7072)
improve concat_list with empty list error message (#7236)
fix groupby_dynamic's binning when index_column is time-zone-aware (#7278)
fix preservation of microseconds when converting Python datetime (#7271)
fix us precision of datetime to anyvalue conversion (#7268)
no panic on empty cross join (#7266)
raise error on ambiguous filter predicates (#7265)
handle concat_list with first lit value (#7235)
respect schema in DataFrame initialisation for time-zone-aware datetime (#7240)
ensure every type is properly normalised (for groupby_dynamic and groupby_rolling) (#7238)
add test of median function in lazy mode (#7224)
dont lose precision in pl.date_range due to floating point arithmetic (#7229)
Conversion of negative timedelta to polars duration (#7209)
ensure parametric testing cols=int definition respects allowed_dtypes (#7213)

🛠️ Other improvements

Fix read/write_database tests (#7327)
Rename scan_ds to scan_pyarrow_dataset (#7320)
don't run tests that write to disk by default (#7321)
rename read_sql to read_database (#7315)
Address git2 vulnerability (#7309)
Correctly deprecate DataFrame.pearson_corr (#7307)
Skip write_excel doctests (#7306)
Run pytest-xdist with worksteal (#7304)
Rename pearson_corr & spearman_rank_corr (#7014)
refactor(python) Split io module per type (#7295)
Move _html module to dataframe module (#7256)
Enable strict for ruff TCH lints (#7234)
better select on map_dict dtype (#7217)
add warning of mmap to ipc docstring (#7216)
exit non-zero on fix from ruff (#7215)
ensure that DataFrame and LazyFrame init params don't diverge (#7214)

Thank you to all our contributors for making this release possible! @MarcoGorelli, @aldanor, @alexander-beedie, @coinflip112, @csko, @dependabot, @dependabot[bot], @ghuls, @josemasar, @josh, @mslapek, @nrebena, @ozgrakkurt, @papparapa, @ptiza, @rben01, @ritchie46, @sorhawell, @stinodego, @universalmind303, @xyning and @zundertj