Yes, after you upgrade the app, you will be prompted to backup your contacts as a precaution. This backup is stored locally on your iPhone in the vCard format. You can view your backups by going to Contacts Sync > Contacts > Backup Contacts.
In addition to the backups made by the app, syncing contacts itself creates a backup, in the sense that your contacts will exist in 2 accounts, such as iCloud and Google.
This help article relates to the iPhone app called "Contacts Sync" which can be downloaded here:
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