SyncBackPro V11 and SyncBackSE V11 supports Deflate, Deflate64, BWT, BZip2, LZMA, LZMA2, XZ and Zstandard. They also support the filename encryption methods used by SecureZip and 7zip. 


SyncBackPro V10 does not support LZMA2, XZ, Zstandard or the 7zip filename encryption.

SyncBackSE V10 supports 
Deflate, Deflate64, and BWT. It also supports the filename encryption method used by SecureZip. It does not support BZip2, LZMA, LZMA2 nor the filename encryption method used in 7zip.

SyncBackFree supports only Deflate compression.

Files compressed with Deflate can be opened by practically any type of compression utility. The disadvantage is that it is least efficient compression method. They are stored in a standard Zip file format.


Deflate64 is an enhanced version of Deflate, and can be opened by most compression utilities. A standard Zip file format is used.


BZip2 is an advanced compression method that is support by some compression utilities, e.g. WinZip 10 or newer and 7Zip. A standard Zip file format is used.


BWT compressed files can only be opened with SyncBackSE or SyncBackPro. A standard Zip file format is used, but the compression method is BWT.


LZMA uses an improved and optimized version of the Lempel-Ziv (LZ77) compression algorithm, backed by a Markov chain range encoder. It uses a variable dictionary size. It is compatible with some compression programs, e.g. WinZip 12. LZMA typically provides much better compression than the Deflate and Deflate64 algorithms at the expense of speed and memory usage when compressing. It also typically provides compression ratios a little better than BZip2/BWT while being a little faster.


LZMA2 uses the same compression and encryption found in 7zip. It is supported by SyncBackPro and SyncBackSE V11.


XZ is essentially LZMA2 but uses a different compression engine. It is supported by SyncBackPro and SyncBackSE V11. A standard Zip file format is used (not the XZ file format). 


Zstandard is a newer compression algorithm created by Facebook. A standard Zip file format is used.


If filename encryption is used then the compressed files can be opened with SyncBackPro, SyncBackSE, SecureZip (by PKWare) and 7zip.