A collection of breaking and non-breaking changes we'd like to make in LH v8. If you come across any API that would be nice to change, add it here :)

Summary

metrics & perf

• reweight metrics in perf score · PR #12577
• TBT realignment with field FID (go/wtsiw) · PR #12576
• replace CLS with NLS (partially nonbreaking) · Update CLS definition #12350
  • add allframes to new CLS · PR #12476
  • replace CLS with new version, remove old variants · PR #12554
  • update PSI to m90 to support allframes
• update FCP score curve · PR #12556

release notes

• Score changes summary/faq · PR #12597
• PSI/CRUX release notes

i18n

• fresh import · PR #12591

breaking changes

• rename uses-webp-images to modern/nextgen-image-formats (or something) · PR #12535, stack-packs#63
• ImageElement artifact shape fixes (ImageElement gathererer fixups #12077) · PR #12568
• remove firstCPUIdle? remove estimatedInputLatency? · PR #12553
• remove postMessage loading from treemap app · PR #12519

deps

• drop intl polyfill · PR #12426
• update chrome-launcher to 0.14.0 (node version change) · PR #12507
• update axe-core to 4.2.1 · PR #12575 PR #12536

Punted to v9

• possibly recalibrate throttling multipliers · Improve BenchmarkIndex to land device targeting #9085
• redirects performance consistency observed v. simulated · Improve handling of redirects, navStart #8984
• move to minimum Node 14
• drop TagsBlockingFirstPaint gatherer and base render-blocking-resources on LinkElements and ScriptElements instead · misc: add type checking to TagsBlockingFirstPaint #11841 (comment)? probably pending decision on AMP special handling