# Supported browsers in vNext

**URL:** <https://discourse.aurelia.io/t/supported-browsers-in-vnext/2934>\
**Category:** vNext\
**Created:** [September 17, 2019, 1:10pm UTC](https://discourse.aurelia.io/t/supported-browsers-in-vnext/2934 "2019-09-17T13:10:38Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![petronellius](https://yyz1.discourse-cdn.com/flex027/user_avatar/discourse.aurelia.io/petronellius/32/1617_2.png) [@petronellius](https://discourse.aurelia.io/u/petronellius)\
**Post date:** [September 17, 2019, 1:10pm UTC](https://discourse.aurelia.io/t/supported-browsers-in-vnext/2934/1 "2019-09-17T13:10:38Z")

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Which browsers will be supported in next version?  
I could see, Proxy api is used to observer object and its properties. Will it be the only way how objects are observed?

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**Author:** ![fkleuver](https://yyz1.discourse-cdn.com/flex027/user_avatar/discourse.aurelia.io/fkleuver/32/994_2.png) [@fkleuver](https://discourse.aurelia.io/u/fkleuver)\
**Post date:** [September 18, 2019, 11:32am UTC](https://discourse.aurelia.io/t/supported-browsers-in-vnext/2934/2 "2019-09-18T11:32:30Z")

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The plan is evergreen + IE11. We’re still working on a properly configured build that produces an IE11-compatible output but it will come.

We’re actually not using proxies by default. The observation mechanism is still largely the same as in v1.  
We do have an opt-in to use proxies which adds some “automagic”-ness to a few things like computed observation (in v1 you need to explicitly declare dependencies, in v2 dependencies are auto discovered by proxies), and the default observation mechanism can be configured to use proxies instead of getters/setters. However, this is disabled by default because it performs worse on mutations.

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**Author:** ![petronellius](https://yyz1.discourse-cdn.com/flex027/user_avatar/discourse.aurelia.io/petronellius/32/1617_2.png) [@petronellius](https://discourse.aurelia.io/u/petronellius)\
**Post date:** [September 19, 2019, 12:40pm UTC](https://discourse.aurelia.io/t/supported-browsers-in-vnext/2934/3 "2019-09-19T12:40:54Z")

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It’d be great if dependencies for computed properties don’t need to be configured manually. I have just read some articles about proxies and it looks like their usage can degrade performance a lot.  
[https://thecodebarbarian.com/thoughts-on-es6-proxies-performance](https://thecodebarbarian.com/thoughts-on-es6-proxies-performance)  
[https://jsperf.com/es6-proxy/7](https://jsperf.com/es6-proxy/7)

Hopefully, their performance will be better with newer browsers versions.