### Added
- Add B3 headers injection and extraction #1629
- Collect http.client_ip #1621

### Changed
- Filter x-datadog-tags for _dd.p. prefix and add DDTrace\add_distributed_tag #1618
- Rename query string obfuscation variable #1630
- Collect query string by default and obfuscate #1615
- Update regex to account for URL encoding #1622
- Update library versions used in tests + support plesk paths #1632
- Remove service name propagation #1635, #1636
- Add integration loaded output for deferred integrations on DD_TRACE_DEBUG=1 #1639
- Reduce memory footprint of strpprintf #1640
- New implementation for hooks #1617
- (PHP 5) Add g1a/composer-test-scenarios and symfony/flex to composer allow-plugin list #1647

### Fixed
- Fix crash with numerical value in $_SERVER array #1634
- Fix missing query string on http.url from integrations #1642

### Internal changes
- Add link to compatibility requirements in README.md #1610
- Manually build PHP for randomized tests images #1616
- Eliminate PHP 5 references from master #1626
- Remove PHP 5 from CI and fetch it instead from the latest PHP-5 branch build #1624
- Fix test_web on PHP 8.0 #1631
- Add g1a/composer-test-scenarios and symfony/flex to composer allow-plugin list #1637
- (PHP 5) Run Wordpress testsuite actually against PHP 5 #1638
- Test debian bullseye instead of stretch in CI #1644
- Update rel env to use 0.75.0 (#1620)
- Disable clang format check in CI #1619
- Add one more allow-plugins in root composer.json #1646
- (PHP 5) Add g1a/composer-test-scenarios and symfony/flex to composer allow-plugin list #1647

## Profiling (v0.7.0)
# Changed
- Do not upload empty profiles. See DataDog/dd-prof-php@e03ff23e5216f863061285e13170d011d0c04bc8 for details.

# Fixed
- Fix a small memory leak with env var handling.

# Added
- Add SAPI as profile tag.
- Add support for `DD_PROFILING_EXPERIMENTAL_CPU_TIME_ENABLED` env var. It previously supported this functionality under a different, undocumented name.