Bug ID 521455: Images transcoded to WebP format delivered to Edge browser

Last Modified: Oct 06, 2020

Bug Tracker

Affected Product:  See more info
BIG-IP AAM(all modules)

Known Affected Versions:
11.5.0, 11.5.1, 11.5.1 HF1, 11.5.1 HF10, 11.5.1 HF11, 11.5.1 HF2, 11.5.1 HF3, 11.5.1 HF4, 11.5.1 HF5, 11.5.1 HF6, 11.5.1 HF7, 11.5.1 HF8, 11.5.1 HF9, 11.5.10, 11.5.2, 11.5.2 HF1, 11.5.3, 11.5.3 HF1, 11.6.0, 11.6.0 HF1, 11.6.0 HF2, 11.6.0 HF3, 11.6.0 HF4, 11.6.0 HF5

Fixed In:
12.0.0, 11.6.0 HF6, 11.5.3 HF2

Opened: May 05, 2015
Severity: 3-Major
Related AskF5 Article:


The Microsoft Edge browser does not support, and cannot render WebP format images. The AAM image optimization framework improperly classifies the Edge browser as being capable of supporting WebP and delivers WebP-transcoded images to such clients.


Some images will fail to render on the Edge browser.


The AAM system's image optimization as well as the "optimize for client" setting must both be enabled, and the associated acceleration policy and application associated with one or more virtual servers.


Disable the "optimize for client" attribute in the applicable policies' acceleration assembly settings.

Fix Information

Transcoded WebP images are no longer served to the Edge browser. By default, transcoded JPEG-XR is also no longer served to the Edge browser, but the db variable ccdb.allow.edge.jpegxr may be used to override this.

Behavior Change