Rename parameter by to group_by in DataFrame.upsample/group_by_dynamic/rolling (#14840)
Rename from_repr parameter from tbl to data (#15156)

🚀 Performance improvements

load bits one word at a time for BitmapIter (#15333)
Ipc exec multiple paths (#15040)
add SIMD support for if-then-else kernels (#15131)

✨ Enhancements

Remove 'FileCacher' optimization (#15357)
check input type in entropy (#15351)
Implements arr.n_unique (#15296)
CSE don't scan share if predicate pushdown predicates don't match (#15328)
Add read_database support for SurrealDB ("ws" and "http") (#15269)
Only allow inputs of type Sequence in from_records (#15329)
In hypothesis testing strategies, enable Decimal strategy by default (#15321)
Remove cached nodes when finished (#15310)
Full plan CSE (#15264)
More robust handling of async database calls (#15202)
Add name parameter to GroupBy.len method (#15235)
Add IR for expressions. (#15168)
Improve read_database when reading from Kùzu graph database (#15218)
Warn if map_elements is called without return_dtype specified (#15188)
Add support for async SQLAlchemy connections to read_database (#15162)
Infer time_unit in pl.duration when nanoseconds is specified (#14987)
Add strict parameter to from_dict/from_records (#15158)

🐞 Bug fixes

Return correct dtype for s.clear() when dtype is Object (#15315)
ensure first datapoint is always included in group_by_dynamic (#15312)
Non-exhaustive patterns: arrow-schema::DataType in polars-arrow (#15250)
use dynamic stacks for problematic recursive functions (#15355)
Adding default ddof for Series.list.std and Series.list.var (#15267)
Raise properly for slices not supported by LazyFrame (#15331)
Propagate strictness in from_dicts (#15344)
Raise error when schema_overrides contains nonexistent column name (#15290)
Enforce integer dtype input for int_range and int_ranges (#15339)
Preserve Decimal precision when constructing empty Series (#15320)
Fix cache dot visualization (#15311)
Handle special case correctly when slicing a LazyFrame (#15297)
Properly propagate strict flag when constructing a Struct Series from any values (#15302)
Consistent expansion of nested struct data during DataFrame init from dict (#15217)
Raise when join projects name with suffix that doesn't exist (#15256)
Ensure ooc_start is set (#15255)
Fix bug where rolling operations were ignoring check_sorted in some cases (#15227)
Fix lazy schema for rle expression (#15248)
incorrect negative offset in multi-byte string slicing (#15140)
do not clamp negative offsets to start of array prematurely (#15242)
allow null index in list.get and array.get (#15239)
Avoid loading all columns in read_parquet when columns parameter is specified (#15229)
properly support nulls_last + descending (#15212)
fix nested runtime panic (#15216)
Block rounding/truncating to negative durations (#15175)
Ensure the cs.temporal() selector uses wildcard time zone matching for Datetime (#13683)
Consistently raise TypeError on constructor failure (#15178)
Properly propagate strictness in some constructor cases (#15166)
Fix constructing a Series from a list of Series with given dtype (#15144)

📖 Documentation

Fix time unit in timestamp example (#15281)
Fix link to renamed method (.list.lengths -> .list.len) (#15228)
Update Excel and database pages in user guide (#14721)
Add examples for Series.search_sorted (#14737)
Correct the definition of an expression in the user guide (#14750)
Add a note about the behaviour of lower/upper bounds for is_between, and add an example (#15197)

📦 Build system

Update Cargo lock (#15370)

🛠️ Other improvements

Memory usage test infrastructure, plus a test for #15098 (#15285)
Update CODEOWNERS (#15352)
remove try_apply_values (#15336)
always use non-legacy float_sum for mean (#15343)
remove legacy bitmap module (#15335)
Fix test not writing to temporary directory (#15318)
Reorganize tests for clear operation (#15304)
Rename Cache[count] to Cache[cache_hits] (#15300)
Cleanup file_caching optimization call (#15299)
Minor refactor of PyDataFrame.from_dicts (#15274)
remove 'fast-projection' node (#15253)
cleanup column names in optimizer (#15252)
remove left_most_input_name from expr ir (#15251)
add AlignedBitmapSlice (#15171)
Run non-benchmark tests in benchmark workflow (#15207)
Add wrapping_abs to arithmetic kernel (#15210)
remove raw buffers from BinViewArray (#15206)
Enable RUST_BACKTRACE=1 in the CI test suite (#15204)
Split read_database functionality into cleaner module structure (#15201)
Clean up some of the AnyValue conversion logic (#15190)
remove parts of legacy bit_util (#15169)
remove legacy arrow compute (#15164)
Split up dataframe module in PyO3 bindings (#15165)
Remove unused private constructors (#15160)

Thank you to all our contributors for making this release possible! @MarcoGorelli, @alexander-beedie, @braaannigan, @c-peters, @cojmeister, @deanm0000, @dependabot, @dependabot[bot], @itamarst, @kszlim, @mbuhidar, @mcrumiller, @mickvangelderen, @orlp, @petrosbar, @reswqa, @ritchie46, @rob-sil, @sportfloh, @stinodego and @yutannihilation