How does browser cache work?
The browser requests some content from the web server. If the content is not in the browser cache then it is retrieved directly from the web server. If the content was previously cached, the browser bypasses the server and loads the content directly from its cache.
Why do you get this issue?
As the default, Wilcity always appends “the Theme / Plugin version to all script urls”.
EG: https://wilcity.com/wp-content/themes/wilcity/assets/production/js/index.min.js?ver=1.1.7.4.4
After updating to a the new version, the script will look like this https://wilcity.com/wp-content/themes/wilcity/assets/production/js/index.min.js?ver=1.1.7.4.5
As you can see, the script url changed after updating, so it won’t use browser cache anymore.
To speed up the website, We need to use a CDN / a Cache plugin, but some of them will remove “the theme version in the script”, for instance, It will include
https://wilcity.com/wp-content/themes/wilcity/assets/production/js/index.min.js
instead of
https://wilcity.com/wp-content/themes/wilcity/assets/production/js/index.min.js?ver=1.1.7.4.5
So, Even you updated to a new version, it still include https://wilcity.com/wp-content/themes/wilcity/assets/production/js/index.min.js
=> As How does browser cache work? => It still uses the old script instead new script.
How can You resolve this issue?
There are 2 solutions to resolve this issues:
- If the CDN / Plugin provides “Turn off removing the them version in the script”, You should enable it
- Flush cache after updating to new version (Plugin cache + CDN cache)
