Error reading OPL files which does not contain "filename" attribute

from majis import read_opl
opl_fname = '/Users/nmanaud/workspace/majis/juice_preops/PLANNING/SCENARIOS/S011_01_TR03_331122_331220/TIMELINE/OPL_SOC_S011_01_S02P00.json'
read_opl(opl_fname)

produces this error:

---------------------------------------------------------------------------
KeyError                                  Traceback (most recent call last)
Cell In[4], line 3
      1 from majis import read_opl
      2 opl_fname = '/Users/nmanaud/workspace/majis/juice_preops/PLANNING/SCENARIOS/S011_01_TR03_331122_331220/TIMELINE/OPL_SOC_S011_01_S02P00.json'
----> 3 read_opl(opl_fname)

File /opt/miniconda3/envs/mos_ops_env/lib/python3.12/site-packages/majis/opl/reader.py:36, in read_opl(fname, flat, only)
     34     events = read_opl_csv(f)
     35 case '.json':
---> 36     events = read_opl_json(f, only=only)
     37 case _:
     38     raise ValueError(f'Invalid OPL file input: {fname}')

File /opt/miniconda3/envs/mos_ops_env/lib/python3.12/site-packages/majis/opl/reader.py:92, in read_opl_json(fname, only)
     77 def read_opl_json(
     78     fname: str | Path,
     79     only: str | list | bool | None = 'MAJIS',
     80 ) -> list[EventWindow]:
     81     """Read OPL file in JSON format.
     82 
     83     Note
   (...)     90 
     91     """
---> 92     return read_itl_json(fname, fmt='OPL', only=only)

File /opt/miniconda3/envs/mos_ops_env/lib/python3.12/site-packages/majis/itl/json/reader.py:32, in read_itl_json(fname, fmt, only)
     29     schema.validate(content)
     31 # Check filename match the one in the file
---> 32 filename = Path(content['header']['filename'])
     33 if not filename or filename.name != Path(fname).name:
     34     raise FileNotFoundError(filename)

KeyError: 'filename'