In case of necessity, X-Cart allows partial updates.
To proceed:
Click the Lock icon in the top right corner of the screen to unlock the selective update option;
Select the add-ons you want to update;
Proceed further as with the regular update.
NB: We can not guarantee the proper operation of your store after running a partial update. Use the selective update feature at your own risk, and only if you know exactly what you are doing.