⚠️ Deprecations Deprecate casting numeric types to categoricals (#28349) Deprecate cat.get_categories() and cat.to_local() (#28299) Deprecate LazyFrame.profile() (#28275) Deprecate casts from non-nested dtypes into Lists (#28193) Deprecate bitwise ops between integers and booleans (#28186) Deprecate list/arr.to_struct() calls that don't pass field names (#28243) Rename missing_utf8_is_empty_string to empty_string_is_null (#28173) 🚀 Performance improvements Split multiplexers that directly scan from in-memory DataFrame (#28376) Make DNS cache global (#28352) Do not remove cache if predicates not pushed to all inputs (#28341) Environment variable for logging slow DNS lookup (#28211) Pre-partition on left, right and semi joins on hive partitioned data (#28374) Rewrite inner joins on hive partitioned data to a union of partitions filtered joins (#28327) Tighten redundant comparisons and propagate filter constraints (#27999) Canonicalize predicates (#28212) Remove excess memory copy in streaming IPC sink (#28141) Parallelize scan_iceberg resolve (#28168) Chunk-aware morsel splitting on single-file IO sink (#27950) Don't allocate for full_null() with small lengths (#28181) Use monotonic deque for rolling min_by/max_by (O(n)) (#27436) ✨ Enhancements Pre-partition group-by on hive keys (#28444) Add ewm_sum and ewm_sum_by #28151 (#28215) Serve stale records from object_store DNS cache (#28256) Make partition_hive an opt flag (#28345) Add scan_arrow_c_stream (#28340) When displaying IRExprs, only add parentheses when needed for disambiguation (#28319) Support Iceberg field initial-default in native scan_iceberg (#28324) Show only differing dtypes in assert_frame_equal error (#27816) Expose ewm and rolling *_by expressions in Python visitor (#28286) More accurate rolling moments (#28309) Remove hard block on native scan for Iceberg V3 tables (#28277) Add Series.degrees/radians and clarify trig functions use radians (#22961) Merge sorted with multikey (#28067) Add list expression which consistently packs elements together into new List type (#27990) Add read_database Arrow fast-path for "python-oracledb" (#28230) Optimize joins with redundant equi-join keys (#28017) Implement missing datetime options for CastColumnsPolicy (#28084) Add Expr.cat.to and Expr.cat.physical (#28096) Add POLARS_OOC_DISK_BUDGET_MB (#28045) Add build side preference parameter for join (#28154) 🐞 Bug fixes Avoid panic when union slice skips all rows (#28420) Solve panic in dt.replace when there were multiple chunks (#28437) Propagate is_scalar from the input to the output of .sort() and .sort_by() (#28438) Resolve CSV column names overwrite in DSL->IR conversion (#28383) Avoid IEJoin rewrite for Categorical comparisons (#28427) Do not rewrite sort().reverse() to sort(descending=True) when maintain_order=True (#28403) Ensure BinaryView offset+len does not exceed i32::MAX where possible (#28048) Invalid offset in strptime (#28388) Incorrect schema type for decimal <-> primitive division (#28373) Panic in in-memory CSEE handling (#28371) Fix offset in arrow ffi export of sliced struct arrays (#28369) Fix cross filter not applied with sink and CSE (#28297) Fix panic on projection pushdown with caches (#28280) Fix write_json() null values in Array columns being written incorrectly as null (#28330) Fix EntityTooSmall on sink_ipc to S3 (#28255) Raise error instead of silent wrapping for select(len()) (#28355) Float16 groupby aggregates (#28361) Respect lexical ordering of Categorical in top_k/bottom_k (#28359) Support dtype-list schema overrides in scan_csv (#28226) Resolve unknown type in fused multiply add (#28321) Honor aws_checksum_algorithm when provided (#28328) Remove usage of deprecated pyarrow.feather.read_table (#28323) Fix regression in sourcing HF_TOKEN (#28317) Raise on addition/subtraction between temporal and non-temporal Series (#28266) Avoid panic constructing Series from unaligned numpy arrays (#28120) Rewrite with_columns on empty df to select during DSL -> IR (#28298) Fix sink deadlock regression (#28296) Avoid panic when consumer of vertical concat is done (#28272) Harden IPC mmap API (#28258) Classify S3 region request failures as IO errors (#28225) Incorrect inner dtype in ArrayChunked::from_aligned_values (#28249) Raise on implode of Object dtype instead of creating invalid List(Object) (#28246) Return null not 0 for the first unbiased ewm_var/ewm_std value (#28235) Database appends with ADBC shouldn't require "CREATE" privileges unless the table is confirmed not to exist (#28228) Avoid slice pushdown panic on shared cache inputs (#28157) Incorrect dtype for Unknown right literal in arithmetic (#28184) Remove unnecessary unsafe Python object downcast (#28189) Normalize non-native byte order in numpy array construction (#28197) Use-after-free in numpy ufunc FFI (#28195) Unpickling for pl.when().then() (#28165) Reduce unknown casts (#28145) Consider a rolling_rank position invalid if ost.len() < min_samples (#28142) Incorrect broadcast with empty len in pl.concat_list (#28134) 📖 Documentation Update comparison page (#28418) Update GPU support documentation with the cudf-polars 26.06 release (#27830) Fix dev docs being canonical for SEO (#28306) Document experimental HDFS support on-premises (#28115) Add Series.degrees/radians and clarify trig functions use radians (#22961) Add polars-bio to community plugins (#28103) Add AWS Marketplace walkthrough to Cloud User Guide (#28214) Correct merge_sorted() docs also for DataFrame (#28183) Clarify DataFrame.remove combines predicates with AND (#28171) Update config reference (#28150) Correct that merge_sorted() null inputs should be nulls first (#28177) Clarify parts of the Polars Cloud and On-prem user guide (#28170) Add On-Premise release 0.6.3 to releases page (#28175) Update PolarsCloud snippets for 0.9.0 release (#28166) Fix to_titlecase incorrectly claiming alphanumeric separation (#28136) 📦 Build system Set the default dev profile to line-tables-only (#28358) Reduce binary size by optimizing for size in the SQL transpilation (#28336) 🛠️ Other improvements Update AI policy for comments (#28436) Fix flaky ordering expectation in top_k_by (#28435) Ignore all deprecation warnings in Python doctest (#28398) Re-work shuffle parameter for sample() (#27460) Ignore deprecation warnings on to_struct() in doctest (#28370) Update spin dependency to v0.10.1 (#28360) Bloat dispatch reduction (#28337) Show only differing dtypes in assert_frame_equal error (#27816) Accept IR in optimize (#28318) Annotate untyped module constants (#27907) Remove unencountered deny entries (#28260) Bump crossbeam-epoch dependency (#28259) Change object_store custom DNS resolver patch to rev-based (#28241) Mark shape tests as passing (#28133) Attribute annotations for *GroupBy (#27903) Clarify AI policy, explicitly forbid agents from interacting with our repository (#28206) Tighten first-time-contributor screenshot requirements (#28207) Covariant classinstmethod and attribute annotation (#27904) Ignore quickxml DoS rustsec (#28185) Update typos to v1.48.0 (#28162) Thank you to all our contributors for making this release possible! @0guban0v, @AnirudhRahul, @Bharath-970, @CodingSelim, @EndPositive, @Jesse-Bakker, @Kevin-Patyk, @LarryHu0217, @MarcoGorelli, @MatteoPossamai, @TNieuwdorp, @alex-h-sun, @alexander-beedie, @azimafroozeh, @borchero, @dancsi, @dependabot[bot], @dsprenkels, @harrywhalen, @jorenham, @kdn36, @makinzm, @malhotrashivam, @mdavis-xyz, @mikhail5555, @mkzung, @mroeschke, @nameexhaustion, @orlp, @r-brink, @raphaelroshan, @ritchie46, @tylerriccio33, @useredsa, @wence-, @yannbolliger, @zichen0116 and dependabot[bot]