IOS XE - Differences between 16 and 3 releases

Hello all,

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I'm currently looking at a 3850 stack of 2 switches we are using as our core switches for a branch office. They are running a version of IOS XE 3.6E, and I have done a little reading around after checking the 'Suggested Release' on Cisco's website and discovering that there are no suggested releases for IOS XE 3 at all.

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I've read that people seem to think IOS XE 16 will replace IOS XE 3 at some point and that IOS XE 3 will stop being developed on, so I have been thinking about doing an upgrade on the stack.

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I've used the Software Release Compare tool from Cisco and there are a lot of differences. For instance, IOS XE 3.6E has 243 unique features, whereas IOS XE 16.3 has only 95. There are a lot of common features, but taking a look through the features only in IOS XE 3.6E, there are some like IEEE 802.1x (Open Authentication, Voice VLAN, Guest VLAN, and a lot of others). There are some IEEE 802.1x features in IOS XE 16.3, but only 2 that are unique to the image. The common IEEE 802.1x features are only VLAN Assignment, Authenticator and RADIUS Accounting.

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So my question is, are there actually key features (think common deployments) from IOS XE 3 that aren't in IOS XE 16? If so, what is the point of IOS XE 16? I don't want to upgrade and find out that a key feature doesn't work anymore.

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Any advice or help is appreciated.