Remove old semantic conventions from HTTP libraries - 2/26/2026

[hannahramadan]

To facilitate the migration to stable HTTP semantic conventions, issue #1116 tracked the introduction of the OTEL_SEMCONV_STABILITY_OPT_IN environment variable for HTTP libraries. This environment variable allowed users to opt-in to the new stable conventions, choosing if they wanted to emit the old semantic conventions, the stable one, or both.

The agent is required to maintain this bridge for 6 months, after which it may drop the environment variable and emit only the stable HTTP and networking conventions. The final HTTP library, Net:Http, was released on August 26, 2025. We are able to remove this environment variable and only emit stable HTTP conventions for all libraries on February 26, 2026.

We should remove the dup and old files and folders from the following instrumentations, leaving only the stable ones. These are the PR's to 'undo':

• HTTP.rb: feat: http semconv opt in files #1547
  • Related: fix: update span name when semconv stability is enabled #1570
• Rack: feat: Rack semantic stability opt in #1594
  • Note changes to action_pack and sinatra
• Net::Http: feat: NET::HTTP semantic convention stability migration #1572
• HTTPClient: feat: Begin HTTPClient semantic convention stability migration #1588
• Rest::Client: feat: rest-client HTTP semantic convention stability migration #1568
• Excon: feat: excon HTTP semantic convention stability migration #1569
• Faraday: feat: Faraday semantic convention stability opt in #1592
• Ethon: feat: Ethon HTTP semantic convention stability migration #1561
• HTTPX: feat: HTTPX semantic convention stability opt in #1589