## All products
### Added
- Add support for file based configuration (library-config) #3068
## Tracer
### Added
- Add DDTrace\try_drop_span() API #3136
- Add support for PDO::connect #3125
- Add span creation and close handlers #3123
- API Gateway Tracing #3116
- Add a Ratchet integration #3115
- Baggage Header Propagation Support #3102
- Crashtracking for windows #3099
### Changed
- Enable 128 bit trace_id logging by default #3163
- Allow whitespace as separator in DD_TAGS #3162
- Implement Disable APM Tracing #3080
### Fixed
- Support both ENOTSUP and ENOSYS in shm_open fallback Datadog/libdatadog#969
- Handle flushing of multiple traces at once #3176
### Internal
- Show actual file and line for occurrence of exceptions as well #3172
- Support ZSTR_PARENT known_string #3106
## Profiling
### Added
- Add profiling and appsec to SSI #3063
### Fixed
- FrankenPHP idle phase #3169
- Add active span null check #3164
- Avoid some OOM panics and avoid long strings #3151
- Fix upscaling of I/O profiles #3146
### Internal
- Add 'tracing' features to capture time spent walking the stack #3094
## Application Security Management
### Added
- Implement API Security Sampling RFC #3117
- Add authenticated user tracking #3114
- Add profiling and appsec to SSI #3063
### Changed
- Upgrade libddwaf #3126
### Fixed
- Emit asm event on user events #3170
### Internal
- Add more logging around stack generation #3096