unable to open new 7z format with LZMA2

[amministra2000srl]

Since 7-Zip 9.0 alpha version, a new compression algorythm is available: LZMA2.

Useless to say that the new archives are incompatible with 2.52ß1 version.

Is it a big problem to get an updated version?

[Jan Patera]

Since 7-Zip 9.0 alpha version, a new compression algorythm is available: LZMA2.

7z 9.0 alpha was released only this week. In general, alpha usually means not yet stable.
Until very recently (actually at least until 9.0 alpha was released), it was not recommended to use LZMA2 in production environment because it was not finished yet and it was possible that files created then would be uncompressable with the next build. We will evaluate the situation and inform you here on the forum.

[amministra2000srl]

it was possible that files created then would be uncompressable with the next build.

I did not consider that. Thanks for your advice and, please, keep on the good job

[Jan Patera]

it was possible that files created then would be uncompressable with the next build.

I did not consider that. Thanks for your advice and, please, keep on the good job

I just noticed this text in the release notes for 9.01 alpha:

Don't use this alpha version for important data. Call "Test" command after each compressing operation.

[amministra2000srl]

Now that 7 Zip has reached 9.04ß, could you please implement the new algorythm to make us test it?

Even a private beta version could be glad

[Jan Rysavy]

For now you are asking alone. Let's wait until we will see more requests or final version 9.

[xm]

The new LZMA2 has several advantages, e.g. faster decompression and better multithreading support (support for splitting work to chunks). But I rather wait for a final version/specification too, before use it for my own data.

[EvaEden~]

Hi there,

for your own trials download
http://puzzle.dl.sourceforge.net/source ... 4_extra.7z
extract 7za.dll and overwrite with it the one in plugins\7zip.

PS: The same procedure e.g. with unrar.dll (newer version under: http://www.rarlab.com/rar/UnRARDLL.exe)

[amministra2000srl]

for your own trials download

I tried with the previous version but did not work. Now it does, thanks for the news.

[Jan Patera]

Now that 7 Zip has reached 9.04ß, could you please implement the new algorithm to make us test it?

The release notes still claim:

Don't use this beta version for important data. Call "Test" command after each compressing operation.

Because there are also other interesting new features introduced in version 9 that we would like to adopt, we monitor the situation.

[Jan Patera]

The release notes still claim:

Don't use this beta version for important data. Call "Test" command after each compressing operation.

Because there are also other interesting new features introduced in version 9 that we would like to adopt, we monitor the situation.

Although still in beta, this disclaimer is no longer appended to release notes. The next version of Salamander (2.53b1/2.53) will be capable of extracting 7z archives with LZMA2.
However, we will add compressing with LZMA2 when the underlaying 7za library leaves the beta status.