{"version":"2.1.225","anchor":"experiment-exposure-telemetry-gains-variation-key-and-stops-","canonical_anchor":"experiment-exposure-telemetry-gains-variation-key-and-stops-","heading":"Experiment-exposure telemetry gains variation_key and stops padding empty strings","tier":"internal","area":"Telemetry","scope":null,"heads_up":null,"url":"https:\/\/changelogs.core-directive.com\/v\/2.1.225\/e\/experiment-exposure-telemetry-gains-variation-key-and-stops-","release_url":"https:\/\/changelogs.core-directive.com\/v\/2.1.225","markdown":"### Experiment-exposure telemetry gains variation_key and stops padding empty strings\n\nExperiment tracking records which variation you got and omits blank optional fields.\n\n**What**\n\nExperiment events now record which variation was seen, and absent optional fields are omitted rather than sent as empty strings.\n\n**Details**\n\n- Adds a `variation_key` field to the experiment event schema.\n- `user_attributes` and `experiment_metadata` default to undefined instead of \"\".\n- The same treatment applies to the generic event's `process` and `additional_metadata` fields.\n\n**Evidence**\n\n`variation_key`\n\n- Area: Telemetry\n- Tier: Under the hood\n- Useful: 1\/5\n- Signal: 0\/5"}