For using Regex Validator Activity, I see I must define my validations in an external file located at Automation Studio > configuration > RegexValidator.xml file.
Whether these validations will be migrated when I migrate my processes which contain Regex Validator activity?
Regex validator validates for email id and phone number and as stated it picks regex from RegexValidator.xml file
Once you migrate say from 18.x to 19.x theRegexValidator.xml file will be present in 19.0 also and your process will run as is. All the validation configured in process will run as is