New language switch has been enabled to anonymous user on July 20 on all pilot wikis. T286459.
We'd like to measure the impact of new language switch on-by-default on anonymous user's language switch behavior.
**Pilot wikis:**
frwiktionary, hewiki, ptwikiversity, frwiki, euwiki, ptwiki, kowiki, trwiki, srwiki, bnwiki, dewikivoyage, vecwiki, fawiki
**Deployment Agenda**
- Deployment date: 2021-07-20
- Catch-up period : 2021-07-20 ~ 2021-07-22
Due to caching, not all users were seeing the new version. The cached articles were displaying the old version of the language switcher. The cache tends to clear completely within two days, which is why we exclude these two days in analysis
- Post-deployment: 2021-07-23 ~ 2021-08-22
**Summary**
- The feature usage data is not in line with the deployment agenda.
-- We observed the new feature click events before deployment date (2021-07-20). The earliest date showing new feature events is on June 22, 2021.
-- The usage of old feature dropped since Jun 22, 2021, instead of the deployment date (2021-07-20)