---
title: "Comment by Abhinav Sharma on \"Zod 4.5 Just Made Your MERN Stack Validation 9x Leaner — Here's What Changed\" | Hashnode"
description: "The datetime strictness change is the classic quiet upgrade trap. Nothing in the code changes, but inputs that passed yesterday start failing validation after t"
url: "https://hashnode.com/posts/zod-4-5-just-made-your-mern-stack-validation-9x-leaner-here-s-what-changed/6ad6199aee694df9c3a1a157/comment/6ad74a8f4009bea95d294831"
---

[Discussion](https://hashnode.com/posts/zod-4-5-just-made-your-mern-stack-validation-9x-leaner-here-s-what-changed/6ad6199aee694df9c3a1a157)

Comment [Zod 4.5 Just Made Your MERN Stack Validation 9x Leaner — Here's What Changed](https://hashnode.com/posts/zod-4-5-just-made-your-mern-stack-validation-9x-leaner-here-s-what-changed/6ad6199aee694df9c3a1a157)

[Abhinav Sharma](https://hashnode.com/@abhinavs1920)

[Oct 20](https://hashnode.com/posts/zod-4-5-just-made-your-mern-stack-validation-9x-leaner-here-s-what-changed/6ad6199aee694df9c3a1a157/comment/6ad74a8f4009bea95d294831)

The datetime strictness change is the classic quiet upgrade trap. Nothing in the code changes, but inputs that passed yesterday start failing validation after the bump. Reading the soundness fixes before the benchmark numbers is the right order.

[Nitesh Kumar Tudu](https://hashnode.com/@nitesh000)

[Oct 20](https://hashnode.com/posts/zod-4-5-just-made-your-mern-stack-validation-9x-leaner-here-s-what-changed/6ad6199aee694df9c3a1a157/comment/6ad74a8f4009bea95d294831#reply-6ad774d7d2cc1538074fdafa)

Yeah, had that issue. That's why had to keep both datetime and datetime with precision as union. That actually solved things in my use case. But yeah, plenty of users are facing this issue.