Howdy SAD27,
Thanks for using the Apple Support Communities! I understand that group chats are having some trouble on your iPhone 5. Let’s take a look and see what we can do. I'm happy to help!
Let's first make sure the iPhone 5 is fully up-to-date on the latest software that it can receive. If there is an update available, please make sure your backup the iPhone before performing the update or performing any resets on your device.
How to back up your iPhone, iPad, and iPod touch
Update your iPhone, iPad, or iPod touch
Next, let's make sure that the time zone is set to automatically update.
How to get updated time zone information for your Apple device
If issues persist, let's do the following.
- Go to Settings > Messages, Turn iMessage off.
- Reset your Network Settings. Tap Settings > General > Reset > Reset Network Settings. This also resets Wi-Fi networks and passwords, cellular settings, and VPN and APN settings that you’ve used before.
- After your iPhone is through restarting, turn iMessage back on.
Please respond back if you continue to have any issues.
Best regards!