OrcaSlicer 2.5 Alpha Brings the H2C and A2L, With Rough Edges

Which Bambu printers each version supports

OrcaSlicer's release notes list the H2C and A2L among the new features. To see exactly what changed for Bambu owners, we compared the Bambu machine profiles in OrcaSlicer's source code at the two release tags. Version 2.4.2 carries profiles for twelve Bambu printers. The 2.5.0 Alpha adds the A2L and the H2C and removes none. We have not run the alpha on an H2C or A2L ourselves: everything on this page comes from the release notes, the source code and OrcaSlicer's GitHub tracker.

The code behind the two new profiles is not new. The pull request that adds H2C and A2L machine support (#14685) was merged on July 13, 2026, six days after 2.4.2 shipped, so every nightly build since then has carried it. What changes with the alpha is that the support now ships in a numbered release with release notes. OrcaSlicer describes its nightly builds as works in progress that may contain bugs or unstable features, and the alpha carries a similar warning of its own.

1. July 7OrcaSlicer 2.4.2, the current stable release, without H2C and A2L profiles.
2. July 13H2C and A2L machine support merged (#14685), in the nightly builds from then on.
3. July 22Per-slot purge tracking for the H2C rack merged (#14800).
4. October 8Mixed nozzle sizes for the H2D and X2D merged (#14125).
5. October 162.5.0 Alpha published, marked as a pre-release.
6. October 17First H2C bug report against the alpha (#16584, feed failure), still open on October 21.
7. October 20H2C nozzle rack filament ID fix merged (#16612), not in the alpha download.

What the H2C gets, and what is untested

For the H2C the notes promise full support, including pre-heating and cooling and multi-color and multi-material printing with the nozzle-changing rack (background: how the H2C and its rack work). The part that matters for filament use: OrcaSlicer tracks which filament sits in each rack nozzle and only purges a nozzle when its filament changes, which, the notes say, keeps filament use and print time close to Bambu Studio's. That tracking is a port of Bambu Studio's own per-slot purge tracking (#14800, merged July 22). The notes give the A2L the same pre-heating and cooling support and say nothing more specific about it.

Four limits, stated in the notes themselves or visible on GitHub in the days after the release:

• Filament Track Switch: untested. Support for Bambu's switch is ported, the notes say, but has not been tested on hardware yet. If your H2C, H2D or X2D runs with the switch, you are the test. What the switch does and does not do: our Filament Track Switch article.
• A feed failure on an H2C is open. On October 17 a user reported that print jobs sliced in 2.5.0-alpha fail on an H2C with "Failed to feed filament to the extruder" (error 07FE-8028-083217), both with the rack nozzles unloaded and with the correct filament preloaded (issue #16584). It was still open on October 21.
• One H2C fix is already newer than the alpha. While looking into that report, a contributor found that OrcaSlicer sent the printer its own filament IDs instead of Bambu's in the request that matches filaments to rack nozzles, so the printer could never match a filament to the rack nozzle that already holds it (#16612). It affects Bambu's own system filaments only. The fix was merged on October 20, four days after the alpha, so it is in the nightly builds but not in the alpha download. According to the pull request, it is not the cause of the feed failure above.
• Calibration with the switch. With a Filament Track Switch installed, the Flow Dynamics calibration page lists every AMS under the right nozzle and offers only the external spool on the left, while Bambu Studio lists each AMS under both. A fix (#16632) was still open on October 21.

For the A2L we found no issue on OrcaSlicer's GitHub since the alpha came out (search on October 21). That is no proof that it works, only that nobody has reported a problem there yet.

Mixed nozzle sizes on the H2D and X2D

The other Bambu headline is for the two dual-nozzle printers. The left and right nozzles of an H2D or X2D can now be different sizes, for example a 0.2 mm nozzle for fine outer walls and a 0.8 mm nozzle for fast infill, the notes' own example. You set each diameter in the sidebar or the printer settings, and OrcaSlicer works out line widths, infill, supports and ironing from the nozzle each filament prints with. This one is recent: it was merged on October 8 (#14125), so it spent about a week in the nightly builds before the alpha.

Ported from Bambu Studio alongside it: each nozzle on a Bambu dual-nozzle printer gets a Flow choice, Standard or High Flow, and speeds, motion limits and many other process and printer settings can be set separately for each nozzle and flow type. Filament profiles can carry their own pressure advance, fan and temperature values for each nozzle variant; profiles that store a single value keep applying it to every variant.

Smaller changes for every Bambu owner

• AMS drying. Start, watch and stop filament drying on an AMS 2 Pro or AMS HT from the Device tab, by clicking the AMS humidity indicator. Ported from Bambu Studio.
• Network plug-in. OrcaSlicer supports Bambu's 02.08 network plug-in series and defaults to 02.08.04, which, the notes say, also loads on macOS 27; plug-in updates apply without a restart. The Device tab adds newer firmware options such as timelapse storage and stopping a filament change, and OrcaSlicer warns when a filament will switch extruders mid-print.
• 3MF by default. Bambu Lab profiles now enable "Use 3MF instead of G-code", so third-party hosts such as SimplyPrint get a .gcode.3mf again, as before 2.4.0. Plain G-code is one setting away in the printer settings.
• Profiles synced with Bambu Studio. Bambu presets, covers and bed models match Bambu Studio's, including the latest X2D machine G-code; OrcaSlicer's own P2S tuning stays.
• New filament IDs. Every filament product now has its own ID. AMS slots and calibration results saved with an old ID match by filament type until you reselect the filament, so look over your AMS slot assignments after the upgrade.
• Third-party filament presets moved. About 700 presets tuned for Bambu printers, for Polymaker, BETA, COEX, Overture, add:north, Numakers, FusRock and AliZ filament, moved to the Orca Filament Library with names and settings unchanged.
• Two fixes worth knowing. With Fan speed-up time or Fan kick-start time set, the Change filament G-code no longer gains a travel move that drove a P1S toolhead into the motor housing (issue #15789). On the H2D, Arrange no longer pushes objects partly off the plate (issue #15727).

Plugins run code on your computer

The feature OrcaSlicer leads with, Python plugins, is not Bambu-specific, but it changes what you install. A plugin can add one-click scripts, step into slicing to reshape layers or rewrite the G-code, and add its own tab or panel; it comes as a file or through Orca Cloud. According to the notes, a plugin must ask your permission before it reaches outside OrcaSlicer's data folder, goes online or starts other programs, and the plugin system is new, with an API that may still change. Treat a plugin like any other program you download: from authors you trust, with that permission prompt read rather than clicked away.

Should you install it?

• H2C owners. The alpha is the only numbered OrcaSlicer release with your printer. If you print through a Filament Track Switch, wait: that path is untested, and the open feed failure (#16584) is on an H2C.
• A2L owners. Same profile situation, no bug reports yet. Worth a try on a model that does not matter.
• H2D and X2D owners. Only the mixed nozzle sizes are new for you, and that code is a week old. Try it if you have the second nozzle size on hand, otherwise wait.
• Everyone else. Stay on 2.4.2 until the stable 2.5.0. The alpha's notes name no date for it.

For comparison, Bambu Studio's own current builds are 2.8.2.61 (stable, August 21) and the 2.8.4 Public Beta (September 22); our notes on the previous Studio beta cover what changed there. If you run OrcaSlicer in LAN mode, our Bambu Connect explainer covers the authorization rules that decide how third-party slicers reach the printer.

Common questions

Does OrcaSlicer support the Bambu Lab H2C?

Yes, from version 2.5.0 Alpha (October 16, 2026), and in the nightly builds since July 13, 2026. The stable 2.4.2 has no H2C profile. Support for the Filament Track Switch is ported but, according to the release notes, not yet tested on hardware.

Does OrcaSlicer support the Bambu Lab A2L?

Yes, from the same 2.5.0 Alpha; the stable 2.4.2 has no A2L profile. We found no A2L bug report on OrcaSlicer's GitHub between the alpha's release and October 21, 2026.

Can the H2D use two different nozzle sizes in OrcaSlicer?

In the 2.5.0 Alpha, yes: the left and right nozzles of an H2D or X2D can be different sizes, for example 0.2 mm and 0.8 mm, and OrcaSlicer works out line widths, infill, supports and ironing from the nozzle each filament prints with. The stable 2.4.2 does not offer it.

Sources

• OrcaSlicer V2.5.0 Alpha release notes (published October 16, 2026, read October 21, 2026)
• OrcaSlicer v2.4.2 release (July 7, 2026)
• Bambu machine profiles in the source at both tags: v2.4.2 and v2.5.0-alpha (compared October 21, 2026)
• Pull requests #14685 (H2C and A2L machine support, merged July 13, 2026), #14800 (H2C per-slot purge tracking, merged July 22, 2026), #14125 (H2D and X2D mixed nozzle sizes, merged October 8, 2026), #16612 (H2C nozzle rack filament IDs, merged October 20, 2026) and #16632 (calibration page with the Filament Track Switch, open on October 21, 2026)
• Issue #16584, "Failed to feed filament" on an H2C (opened October 17, 2026, open on October 21, 2026); GitHub issue search for H2C and A2L since October 16, run October 21, 2026
• OrcaSlicer nightly builds page (description of nightly builds, read October 21, 2026)
• Bambu Studio releases on GitHub (2.8.2.61, August 21, 2026; 2.8.4 Public Beta, September 22, 2026; read October 21, 2026)