The change regarding D meaning day of year in dateFormat functions was introduced (unexpectedly) in cf2021. So you must be migrating from cf2018 or earlier. Some good news: Adobe offered a JVM arg that would switch it back to ignoring the case of that "d". See the cf docs on the dateFormat function.
Or yes, you can change your code. I did a blog post the week this was introduced, and it some folks shared regex search strings for different major editors, to help there. I also offer the jvm arg and how to apply it as well as more on the change :
https://www.carehart.org/blog/2020/11/24/breaking_change_in_cf2021_dateformat_D_vs_d
As for your work to change scopes, I'll point out that while it's good to be done, you could have avoided it. This was a change introduced to both cf2023 AND cf2021 last march. More in a couple of blog posts that may help you:
https://www.carehart.org/blog/2024/3/12/cf_updates_march_2024_possible_breaking_change
https://www.carehart.org/blog/2024/7/18/dont_miss_helpful_feature_identify_implicit_scopes
And as long as you're migrating beware of another important breaking change introduced in an update last June. I have posts on that there as well, from June and July. See the calendar offered in my blog site.
Finally, if you'd like to stay more up to date on such matters, I do blog about each update (to cf and to Java)--including extra info not offered by Adobe, and you can subscribe to my blog via a simple form offered there.
Let us know if the first point above gets you going.