# Announcing C-Blosc2 2.0.0.beta.5
A simple, compressed and fast data store library for C; and persistent too.
## What is new?
This is the fifth beta version, adding pre-filtering functionality and masked decompression. Prefiltering allows to callback arbitrary functions previous to any filter. This can be useful for performing (parallel) computations on chunks.
Also, with masked decompression, it is possible to do partial chunk decompressions. By calling the `blosc2_set_maskout()` prior to `blosc2_decompress_ctx()` has the effect to select the set of blocks to decompress in a chunk. This will be useful for more efficient slicing operation in Caterva.
Last, but not least, C-Blosc2 gained support for ALTIVEC optimzations on Power architecture. These include support for both shuffle and bitshuffle filters. For details, see https://github.com/Blosc/c-blosc2/pull/98
. Thanks to Jerome Kieffer and ESRF for making this happen.
In principle, C-Blosc2 should be backward compatible with C-Blosc, so you can start using it right away and slowly begin to use its new functionality, like the new filters, prefilters, super-chunks and frames. See docs in: https://blosc-doc.readthedocs.io
**IMPORTANT**: Please note that, even if the API has been declared frozen, that does *not* mean that Blosc2 is ready for production yet: internal structures can change, formats can change and most importantly, bugs can be normal at this stage. So *do not assume* that your blosc2 data can be read with future versions.
For more info, please see the release notes in:
Also, there is blog post introducing the most relevant changes in Blosc2:
## What is it?
Blosc2 is a high performance data container optimized for binary data. It builds on the shoulders of Blosc, the high performance meta-compressor (https://github.com/c-blosc
Blosc2 expands the capabilities of Blosc by providing a higher lever container that is able to store many chunks on it (hence the super-block name). It supports storing data on both memory and disk using the same API. Also, it adds more compressors and filters.
## Download sources
The github repository is over here:
Blosc is distributed using the BSD license, see LICENSES/BLOSC2.txt
## Mailing list
There is an official Blosc mailing list at:
- The Blosc Development Team