Starting with version 5, a new archive format, RAR5, is supported, incompatible with the previous one, but also using file extension .RAR. With the introduction of RAR5, the older format is referred to as RAR4. Newer WinRAR versions can still open and create RAR4 archives, but older versions do not support RAR5 archives.
Both the numerous features (authenticity verification, old style extension based arcname.rNN volume names, file comments) are removed from RAR5, and by default RAR5 is slower than RAR4 (default dictionary size for WinRAR v5.x is 32 MB, typically resulting in higher compression ratio and lower speed than WinRAR v4.x with 4 MB).
The software is distributed as a shareware and anyone may use it during a test period of 40 days at no charge.
While archiving with the RAR format is proprietary, Rarlabs supply as copyrighted freeware the source code of the UnRAR unpacker, with a license allowing it to be used in any software, thus enabling others to produce software capable of unpacking, but not creating, RAR archives.
Pack (create) or validate (test) RAR and ZIP archives.
Since version 4.10 (January 2012) WinRAR removes all ZIP limitations now allowing unlimited number of files and archive size. WinRAR now also allows to create multivolume ZIP files. ZIP archives now include Unicode file names.
Since version 4.20 (June 2012) Compression speed in SMP mode has been increased significantly, but this improvement was made at the expense of increased memory usage. ZIP compression now uses SMP as well. The default SMP mode cannot handle text; text compression is significantly worse unless additional switches are used. Also, Windows 2000 compatibility was removed.
Since version 5.00 (September 2013) the new RAR5 archive format is implemented. The new compressed archives cannot be managed by old versions of WinRAR. This new format features a maximum 1 GB dictionary (only in 64-bit version), better multicore support, it removes multimedia, text and Itanium binaries special compression algorithms.
In "About WinRAR" Help menu clicking on the WinRAR logo makes the ocean surf and waves move. Mouse clicking with Shift pressed on the logo causes the appearance of a sailboat above the "R" button which is sailing around in the water.
In the same dialog pressing the book icon causes it to jump like a ball until it rests, and with each bounce, the Windows' exclamation sound can be heard.
Colored comments can be added to WinRAR archives.
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