[IOS] xcode 4 supports both old iOS devices (armv6) and compatible with iPhone and iPad

By default, only armv7, or new iOS devices, including the iPhone
3gs, iPhone 4, iPhone 4 s, iPad, and iPad 2, while iPhone, iPhone 3G, iPod Touch, and iPod Touch 2 belong to armv6 architecture.

1. The steps for compatibility with armv6 and armv7 are as follows:

Project-> Info-> IOS deployment target select 3.0

Project-> build settings-> ubuntures Delete the original standard (armv7), add an armv6, and then add an armv7, right-click the ubuntures row to save and exit (the following save and exit methods are the same)

Project-> build settings-> base SDK keeps latest IOS (IOS 5.1) Unchanged

Project-> build settings-> build active architecture only retains no

As shown in

Targets-> Summary-> deployment target: Select 3.0

Targets
-> Info-> Delete the required device capabilities row

Targets
-> Build settings-> ubuntures: Delete the original standard (armv7), add one armv6, and then add one armv7 (same as the project)

Targets-> build settings-> base SDK retains latest IOS
(IOS 5.1) Unchanged

Targets-> build settings-> build active architecture
Only keep no unchanged

Shows other parameters in targets.

2. Compatibility with iPhone and iPad

Targets-> Summary-> devices select universal.

Then

Targets-> Summary-> deployment info for iPhone/iPad

3. Add ad hoc distribution and distribution options

Project-> Info-> deployments point + sign to add

Then you can

Project-> build settings-> code signing identity

And

Targets
-> Build settings-> code signing identity

Select the signature of the corresponding release version.