iOS如果提示XX证书过期，可以参考下面的帮助，有些必须要及时生成，有些可以晚点。
Certificates
Apple Developer Program membership is required to request, download, and use signing certificates issued by Apple. You must also be the Team Agent or an admin of your development team to request distribution certificates used for submitting apps to the App Store or Mac App Store. For more information on how to use signing certificates, review the App Distribution Guide.
In most cases, Xcode is the preferred method to request and install digital certificates for iOS and OS X. However, to request certificates for the Apple Push Notification service, Passbook, Mobile Device Management (MDM), and Safari extensions, you will need to request and download them from Certificates, Identifiers & Profiles in your account on the developer website.
Expired or Revoked Certificates
Apple Push Notification Service Certificate
You can no longer send push notifications to your app.
Pass Type ID Certificate (Passbook)
If your certificate expires, passes that are already installed on users' devices will continue to function normally. However, you will no longer be able to sign new passes or send updates to existing passes. If your certificate has been revoked, your passes will no longer function properly.
iOS Distribution Certificate (App Store)
If your Apple Developer Program membership is valid, your existing apps on the App Store will not be affected. However, you will no longer be able to submit new apps or updates to the App Store.
iOS Distribution Certificate (in-house, internal use apps)
Users will no longer be able to run apps that have been signed with this certificate. You must distribute a new version of your app that is signed with a new certificate.
Mac App Distribution Certificate and Mac Installer Distribution Certificate (Mac App Store)
If your Apple Developer Program membership is valid, your existing apps on the Mac App Store will not be affected. However, you will no longer be able to submit new apps or updates to the Mac App Store.
Developer ID Application Certificate and Developer ID Installer Certificate (Mac applications)
If your certificate expires, users can still download, install, and run versions of your Mac applications that were signed with this certificate. However, you will need a new certificate to sign updates and new applications. If your certificate has been revoked, users will no longer be able to install applications that have been signed with this certificate.
Apple Worldwide Developer Relations Certification Intermediate Certificate
The Apple Worldwide Developer Relations Certificate Authority issues certificates used by developers for signing third party apps and Safari Extensions, and for using Apple Wallet and Apple Push Notification services. We've issued a renewed certificate that must be included when signing all new Apple Wallet Passes, Apple Push Notifications, and Safari Extensions starting February 14, 2016. Read more.
Note: Apple can revoke digital certificates at any time at its sole discretion. For more information, read the Apple Developer Program license agreements in your account on the developer website.
Compromised Certificates
If you suspect that your Pass Type ID certificate or Developer ID certificate and private key have been compromised, and would like to request revocation of the certificate, send an email to product-security@apple.com. You can continue to develop and distribute passes by requesting an additional certificate from your account on the developer website.
I received an error message saying, "Xcode could not find a valid private-key/certificate pair for this profile in your keychain."
This error message indicates that your system's Keychain is missing either the public or private key for the certificate you are using to sign your application.
This often happens when you are trying to sign and build your application from a different system than the one you originally used to request your code signing certificate. It can also happen if your certificate has expired or has been revoked. Ensure that your app's provisioning profile contains a valid code signing certificate, and that your system's Keychain contains that certificate, the private key originally used to generate that certificate, and the WWDR Intermediate Certificate.
For instructions on how to resolve this error, review the Code Signing support page.
What happens to my Developer ID–signed applications if my Apple Developer Program membership expires?
If your membership expires, users can still download, install, and run your Developer ID–signed applications. However, once your Developer ID certificate expires, you must be an Apple Developer Program member to get new Developer ID certificates to sign updates and new applications.
链接来自：https://developer.apple.com/support/certificates/
