Has Apple slowed my older iPad 4?

No.

The older iPhone battery performance slowdown only affects older iPhone 6 and later iPhone models with degraded battery performance issues.

The iPad 4th generation is ineligible and excluded from upgrading to iOS 11

With the introduction of iOS 11, ALL support for older 32 bit iDevices and any iOS 32 bit apps has ended.

Your iPad 4 is a 32 bit hardware device.

The new 64 bit coded iOS 11 ONLY supports newer 64 bit hardware iDevices and 64 bit software, now.

The iPad 4 is incompatible with this new iOS, now.

No need to panic or worry though.

Your iPad 4th gen will still work and function as it always has, but will no longer receive any more app updates sometime in the foreseeable future.

The 4th gen iPad has had over 5 years of iOS upgrades/updates

The final app updates your 4th gen iPad will receive will be its last!

Your iPad 4 will survive and stay a viable, functioning iPad for a couple more years.

Currently, iPad 4 models are STILL receiving app updates, but look for this change over time.

This is why Apple introduced the new, lower cost 2017 iPad 5 model, in April

Apple is trying to get older iPad 2, 3, 4 and 1st gen Mini iPad users to upgrade to more modern iPad hardware in anticipation of iOS 11, which will render all older 32 bit iDevices obsolete, in time.

Tap on my iPad/iOS performance tips link below and try ALL of the tips.

Slow iPad on iOS 9, 10 or 11!

Good Luck to You!

IPad 4 is nearly 6 years old.

Apple is NOT going to offer the reduced $29 U.S.D. battery replacement price for 4, 5, 6 and 7 year old IPad models.

Ain't going to happen for iPads.

iPhone 6 is only 2 to 2-1/2 years old. Plus, iPhones use smaller battery capacities.

FYI,

My IPad 2 and 3 models, which are older than your IPad 4, are still running fine on iOS 9.3.5 with their original Li-ion battery.

If you tried ALL of my IPad performance tips and your IPad 4 is STILL slow on iOS 10, bring it into your “local” Apple store, have them perform a diagnosis on your IPad and IF Apple techs there determines your IPad 4 needs a new battery replacement, an out of warranty battery replacement will cost you $99 U.S.D..

Good Luck to You!

Apple has admitted to slowing down older iPhones because of ageing batteries, but I haven't seen anything about slowing down older iPads.

See: Apple admits slowing older iPhones