Here is a run down of the tweaks and changes for this month taken from the announcement post on Space Sim Central.
"The Pioneer development team are pleased to announce the release of
Pioneer Alpha 25. This month has seen more visual enhancements with gas
giant rings, terrains and city lighting all receiving improvements. Full
changelog and builds for Windows, Mac OS X and Linux (32 & 64-bit)
are available from the download page.
New features
- Planets with surface ports are now displayed with a blue ring in the system info view (F2,F7) (#1345)
- Catalan translation (#1371)
- Hyperjumps now have sound effects (#1379)
- Terrains have been update, and more terrains added for asteroids (#1349)
- Atmospheric height and appearance is now more realistic (#972, #1278, #1357)
- Atmospheric pressure and temperature now follows a dry adiabatic model (#1363)
- Rewritten gas giant rings, with better transparency and shadows (#1404, #1415)
- Fade building illumination depending on time of day and atmosphere (#1390, #1428, #1427)
Minor changes and tweaks
- On Windows, error messages for graphics are shown in
a message box, so they can be read when the game graphics aren't
working (#1362) - Atmospheric pressure is now displayed in atmospheres instead of bar (#1363)
- Added essential surname-based humour to the name generator (#1403)
- Include more limits and capability information in opengl.txt (#1408, #1410)
- Text
entry widgets (notably the Lua console) now support CTRL+LEFT and
CTRL+RIGHT arrows to jump to word boundaries (#1392, #1372) - Scale all textures to power-of-two dimensions (#1422, #1251, #1035, #923)
Fixes
- Fix some Lua console completion edge cases (#1339)
- Fix Lua error report format for missing objects (#1366)
- Fix bug which prevented some Polish texts showing up (#1382)
- Fix crash when autopilot tried to fly around a gravpoint (#1347, #1344)
- Fix crash when calculating distance to a ship in hyperspace (#1393, #1388)
- Fix shaders to avoid 'varying' value limits on some hardware (#1407, #1409)
- Fix savegames not loading under certain circumstances (#1425, #1412, #1424)
- Clamp planetary mass values to supportable range (#1423, #854)
Script and model changes
- Gas giant rings can now be defined in a custom system using the :rings parameter (#1404)
Internal changes
- Move platform specific code into src/{win32,posix} dirs (#1362, #1369)
- Move video initialisation into Graphics::Init (#1362, #1370)
- Add COUNTOF macro to safely get number of elements in a static array (1386)
- Update scan_enums.py to deal with Unicode byte-order marks (#1389)
- Always used logarithmic depth buffer with shaders (#1410)
- Camera now passed to object rendering methods to make per-object lighting and other effects easier (#1390)
- Many fixes identified by static analysis with PVS-Studio (#1402, #1399)"
Download from either Pioneer's own site Pioneerspacesim.net
Also, you might want to use 7zip to de-archive the Alpha once you have it. Here is a link 7-zip.org