App getting slow in IOS iPad (3rd generation) with Version: 9.3.5 (13G36)

Question

I created a Cross platform mobile application with Ionic1 framework with using angularJS.Recently I upgraded ionic cli and cordova.So ,now the current configurations of the project is following:

global packages:

@ionic/cli-utils : 1.5.0
Cordova CLI      : 7.0.1
Gulp CLI         : CLI version 3.9.1 Local version 3.9.1
Ionic CLI        : 3.5.0

local packages:

@ionic/cli-plugin-cordova : 1.4.1
@ionic/cli-plugin-gulp    : 1.0.2
@ionic/cli-plugin-ionic1  : 2.0.1
Cordova Platforms         : android 6.2.3 ios 4.4.0
Ionic Framework           : ionic1 1.3.0

System:

Node       : v6.9.5
OS         : macOS Sierra
Xcode      : Xcode 8.2.1 Build version 8C1002
ios-deploy : 1.9.1
ios-sim    : 6.0.0
npm        : 3.10.10

I used a client side Socket.Io. in my application (version:1.4.5).Now the problem is that , App working properly in every device but in iPad (3rd generation) Version: 9.3.5 (13G36) , App is working very slow and also all events (like tap , scroll) are slowly working.

Can you please provide me the reason why the application getting slow in IPad ?