A list of all relevant changes to build 11.2 of the JWST Operations Pipeline is provided in this article. 

Build 11.2 was released as a build candidate in January 2025, and installed as an operations build in March 2025. The information provided here focuses mainly on updates to the JWST Science Calibration Pipeline and associated reference files, but includes information relevant to changes in other subsystems that might affect what users see in their data.

Major updates

Data affected by this build

Provided below is a list of science data products in MAST generated by the JWST Science Calibration Pipeline that may be most significantly affected by the updates in build 11.2. The changes listed in the release notes below may affect other modes as well, but many of these will be transparent to the MAST user.

The data and pipeline stages most affected include:

• Stage 1 processing for all NIRISS data and MIRI MRS data.
• Stage 2 processing for all NIRISS data and MIRI MRS data.
• Stage 3 processing for all MIRI MRS data (using per-band instead of per-channel cubes), all imaging mosaics, all NIRSpec MOS and FS data.

Release notes

Build 11.2 of the JWST Operations Pipeline was released as a candidate build on January 3, 2025 and installed as an operations build (11.2) for the Barbara A. Mikulski Archive for Space Telescopes (MAST) on March 4, 2025. The build includes changes to the JWST Science Calibration Pipeline released in version 1.17.0 and patch update 1.17.1 of the jwst calibration pipeline package via the PyPI repository. This release also includes changes to the JWST Science Data Processing subsystem (SDP) version JWSTDP-2025.1.0 which is the DMS sub-system that creates raw (uncal) products used as input to the calibration pipeline.

General changes

• The pipeline now issues a deprecation warning when pipeline steps are executed without specifying either .call() or .run() methods (i.e., silently using Step.__call__() ).  STScI recommends using the explicit Step.call() instead to ensure that all parameter reference files are used properly for a given instrument and observing mode.
• Renamed default branch to main.
• Updated minimum required version of crds to allow for "data release style" contexts.
• When blending metadata don't store columns containing all missing value (nans).

Pipeline modules

• Updated calwebb_coron3 to fix a bug leading to incorrect area extensions and crashes.
• Updated calwebb_spec2 to transfer wcsinfo metadata to new MultiSlitModel created during processing of NIRSpec MSA data.

Product associations

• Added MOSAIC association candidates to list of stage three candidate types requiring members from more than one observation. This fixes an issue with duplication of some associations.

Datamodels

• Updated ModelLibrary to use meta.asn.exptype instead of meta.exptype.

Step Changelist

Changes to specific steps in the pipelines are listed below. 

ami_analyze / ami_normalize / ami_average step

• Change how AMI observables are averaged: average fringe amplitudes and phases before calculating additional observables. Update their error calculation: use covariance of amplitudes/phases (and derived quantities) and standard error of the mean. Code now expects an ASDF filename string for user-supplied affine2d and bandpass input arguments. Examples of how to create such input files are include in the ReadTheDocs documentation.
• Use mask and pupil geometry constants from NRM reference file, and apply affine distortion from commissioning to LG model as default.

assign_wcs step

• Fix some residual issues after the GWCS transform was updated to respect bounding boxes. Now uses the range of points in the TabularModel to adjust the bounding_box in a MIRI LRS FIXEDSLIT observation (although note some outstanding issues with MIRI LRS slit WCS as described in Known Issues above). Ignore the bounding_box in running the inverse WCS transform when computing crpix.
• Catch NaN values in NIRSpec MSA tables for source positions in slit and replace with slit center.
• Use pixel vertices to define s_region instead of pixel centers, resulting in a small adjustment to reported imaging footprints.

background step

• Fixed crash when combining full and subarray observations for background subtraction; use x/y size of science array to avoid array size mismatches and combine multiple integrations of background exposures to create a mean background.
• Apply bitwise operations in correct order when counting good pixels in the background mask during WFSS background subtraction.
• Compute scaling for WFSS background subtraction using error-weighted mean.

combine_1d step

• Fix wavelength sort order for single input spectrum (primarily affecting MIRI LRS for which wavelengths increase with decreasing Y pixel number).

cube_build step

• For moving target IFU data, set RA/Dec header information of "s3d" products according to the mean of input models instead of the first input model.
• Tweak the cube_build spaxel debugging option to provide filename info and match outputs to the stated ordering.

extract_1d step

• Refactor the core extraction algorithm and aperture definition modules for slit and slitless extractions, for greater efficiency and maintainability. Extraction reference files in FITS format are no longer supported. Current behavior for extractions proceeding from extract1d reference files in JSON format is preserved, with minor improvements: DQ arrays are populated and error propagation is improved for some aperture types.
• Set order 2 weights to 1.0 for NIRISS SOSS SUBSTRIP96 data to avoid a spurious flux drop in spectra around 1.5um.

firstframe step

• Add option to not flag the first frame as DO_NOT_USE when a ramp saturates in group 3.

jump step

• Add maximum_shower_amplitude parameter to MIRI cosmic rays showers routine to fix accidental flagging of bright science pixels.

master_background step

• Include resample, pixel_replace and extract_1d into MOS background pipeline.
• Fix ModelContainer handling for user background input.
• Added pixel-to-pixel sigma clipping on input backgrounds in the NIRSpec MOS master_background_mos step. Added option to median filter master background spectrum in both the master_background and master_background_mos steps.

outlier_detection step

• Fix a bug that caused intermediate files to conflict for different slits when a MultiSlitModel was processed.
• Decrease the amount of file I/O required to compute the median when in_memory is set to False.
• For slit spectra, threshold outliers with a median error across exposures instead of input error from the exposure itself.
• Update documentation to clarify the interaction between pipeline-level and step-level --in_memory flags.
• Avoid modifying input and saving duplicate files when resample_data=False.
• Remove deprecated nlow and nhigh parameters from outlier detection step.

refpix step

• Implemented SIRS algorithm instead of running median for side pixels of NIR full-frame data. Running median is still default. 

resample step

• Ignore the bounding_box in the inverse WCS transform in reproject.
• Permit creating drizzled models one at a time in many-to-many mode.
• Updated resample code to support the new drizzle API, see spacetelescope/drizzle#134 for more details.
• Use s_region list to calculate output footprint instead of re-computing via WCS transforms.
• Removed allowed_memory parameter and DMODEL_ALLOWED_MEMORY environment variable.

resample_spec step

• Update NIRSpec spectral resampling to add a missing correction factor in resampled WCS tangent plane transformation.

rscd step

• Updated RSCD step to work on segmented data.

skymatch step

• Ignore the bounding_box of an observation when computing sky statistics.

tweakreg step

• Changed the default values for sharplo, sharphi, roundlo, and roundhi to the values appropriate for the current default algorithm for source finding in the tweakreg step.

JWST Science Data Processing subsystem changes

• SDP now ensures that three GWA TILT-related engineering mnemonics are available in the engineering data before sending NIRSpec filesets on for processing.
• To aid NIRISS WFSS subarray calibration, SDP now overrides the keyword EXP_TYPE to NIS_WFSS for NIS_EXTCAL exposures if the PUPIL keyword value is F090W, F115W, F140M, F150W, F158M, or F200W, and the FILTER keyword value is GR150C or GR150R.
• New values DHS3, DHS4, DHS5, DHS6, and DHS7 were added for keyword READPATT to support use of the NIRCam dispersed Hartmann sensor mode.
• Similarly, there are changes to the dispersed Hartmann sensor values for keyword SUBARRAY:
  • SUB40STRIPE1_DHS -> SUB41STRIPE1_DHS
  • SUB80STRIPE2_DHS -> SUB82STRIPE2_DHS
  • SUB160STRIPE4_DHS -> SUB164STRIPE4_DHS
  • SUB256STRIPE4_DHS -> SUB260STRIPE4_DHS