Hi Team, We are planning to upgrade our application from version 5.3 to latest Pega version. May I know if there’s a document or tool than can help us? Also, how to estimate this upgrade?
@MarkChristianM PRPC 5.3 is a very old unsupported version. See our Pega Extended Support Program article.
all documentation can be found on docs.pega.com.
Updating Pega Infinity for on-premises environments,
On-premises update process for Pega Infinity release 8.4.1 and earlier
You can also carry out a search on PSC. We have many support documents:
Installation and Update Documentation Roadmap
Pega Platform 8.8 Installation and Update Information
If you need more help you can consider contacting your Pega Account Executive who can discuss your needs further.
@MarkChristianM
Depending on the size and criticality of your application it’s maybe worth considering rewriting it on a fresh & latest PEGA version.
From PEGA 8.6 to latest version it’s already a challenge with all technical changes & constraints so from 5.3 upgrading might be a bigger nightmare than starting from scratch 
Regards
Anthony
@MarkChristianM I kind of agree with @Anthony_Gourtay, re-writing the application on the latest version is better than upgrading to latest version. There will always be a backlog when you upgrade from such an old version and you will never be able to fill the gap.