Sourced from python-json-logger's releases.

4.0.0

4.0.0 - 2025-10-06

Added

• Support DictConfigurator prefixes for rename_fields and static_fields. #45
  • Allows using values like ext://sys.stderr in fileConfig/dictConfig value fields.
• Support comma seperated lists for Formatter fmt (style=",") e.g. "asctime,message,levelname" #15
  • Note that this style is specific to python-json-logger and thus care should be taken not to pass this format to other logging Formatter implementations.
• Supports sequences of strings (e.g. lists and tuples) of field names for Formatter fmt. #16

Changed

• Rename pythonjsonlogger.core.LogRecord and log_record arguments to avoid confusion / overlapping with logging.LogRecord. #38
  • Affects arguments to pythonjsonlogger.core.BaseJsonFormatter (and any child classes).
    • serialize_log_record
    • add_fields
    • jsonify_log_record
    • process_log_record
  • Note: functions referring to log_record have not had their function name changed.

Removed

• Remove support for providing strings instead of objects when instantiating formatters. Instead use the DictConfigurator ext:// prefix format when using fileConfig/dictConfig. #47
  • Affects pythonjsonlogger.json.JsonFormatter: json_default, json_encoder, json_serializer.
  • Affects pythonjsonlogger.orjson.OrjsonFormatter: json_default.
  • Affects pythonjsonlogger.msgspec.MsgspecFormatter: json_default.

Thanks @​rubensa

v4.0.0.rc1

4.0.0.rc1 - 2025-09-07

Added

• Support DictConfigurator prefixes for rename_fields and static_fields. #45
  • Allows using values like ext://sys.stderr in fileConfig/dictConfig value fields.
• Support comma seperated lists for Formatter fmt (style=",") e.g. "asctime,message,levelname" #15
  • Note that this style is specific to python-json-logger and thus care should be taken not to pass this format to other logging Formatter implementations.
• Supports sequences of strings (e.g. lists and tuples) of field names for Formatter fmt. #16

Changed

• Rename pythonjsonlogger.core.LogRecord and log_record arguments to avoid confusion / overlapping with logging.LogRecord. #38
  • Affects arguments to pythonjsonlogger.core.BaseJsonFormatter (and any child classes).
    • serialize_log_record
    • add_fields
    • jsonify_log_record
    • process_log_record
  • Note: functions referring to log_record have not had their function name changed.

Removed

• Remove support for providing strings instead of objects when instantiating formatters. Instead use the DictConfigurator ext:// prefix format when using fileConfig/dictConfig. #47
  • Affects pythonjsonlogger.json.JsonFormatter: json_default, json_encoder, json_serializer.

... (truncated)

Sourced from python-json-logger's changelog.

4.0.0 - 2025-10-06

Added

• Support DictConfigurator prefixes for rename_fields and static_fields. #45
  • Allows using values like ext://sys.stderr in fileConfig/dictConfig value fields.
• Support comma seperated lists for Formatter fmt (style=",") e.g. "asctime,message,levelname" #15
  • Note that this style is specific to python-json-logger and thus care should be taken not to pass this format to other logging Formatter implementations.
• Supports sequences of strings (e.g. lists and tuples) of field names for Formatter fmt. #16

Changed

• Rename pythonjsonlogger.core.LogRecord and log_record arguments to avoid confusion / overlapping with logging.LogRecord. #38
  • Affects arguments to pythonjsonlogger.core.BaseJsonFormatter (and any child classes).
    • serialize_log_record
    • add_fields
    • jsonify_log_record
    • process_log_record
  • Note: functions referring to log_record have not had their function name changed.

Removed

• Remove support for providing strings instead of objects when instantiating formatters. Instead use the DictConfigurator ext:// prefix format when using fileConfig/dictConfig. #47
  • Affects pythonjsonlogger.json.JsonFormatter: json_default, json_encoder, json_serializer.
  • Affects pythonjsonlogger.orjson.OrjsonFormatter: json_default.
  • Affects pythonjsonlogger.msgspec.MsgspecFormatter: json_default.

Thanks @​rubensa

• defed00 Release 4.0.0
• c10f1c2 [docs] Fix changelog formatting
• ce8268c Release version 4.0.0.rc1
• a8eca47 [core] Support sequence of strings for Formatter fmt (#55)
• b53b930 [core] Add support for comma format (#54)
• 0428e2b [core] Rename LogRecord/log_record to LogData/log_data (#53)
• ac108d9 [core,json,orjson,msgspec] Remove use of str_to_object (#52)
• 0843f52 [docs] Update version added for exc_info_as_array, stack_info_as_array (#60)
• f36b8b5 [docs] Add style guide (#58)
• 03ad4d1 [docs] Update documentation (#57)
• Additional commits viewable in compare view

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