WinRAR and the RAR file format have evolved over time. Support for the archive format RAR5, using the same RAR file extension as earlier versions, was added in version 5.0; files in the older RAR file format have since been referred to as RAR4. WinRAR versions before 5.0 do not support RAR5 archives.
The RAR5 file format increased the maximum dictionary size to 1 GiB; 11 different compression directory sizes from 1 MiB to 1 GiB are available, with the default in version 5 increased from 4 MiB to 32 MiB, typically improving compression ratio. AES encryption, when used, was increased from 128- to 256-bit. Maximum path length for files in RAR and ZIP archives is increased to 2048 characters.
Options added in v5.0 include 256-bit BLAKE2 file-hashing algorithm instead of default 32-bit CRC32, duplicate file detection, NTFS hard and symbolic links, and Quick Open record to allow large archives to be opened faster.
The RAR5 file format removed comments for each file (though archive comment still remains), authenticity verification, and specialized compression algorithms for text and multimedia files. RAR5 also changed the file name for split volumes from "archivename.rNN" to "archivename.partNN.rar