I do not see any issues as such. All I recommend you is to run the upgrade compatibility check list which would provide you the feasibility study, based on which you could proceed further wihtout having any issues.
Re: upgrading ePO version 5.3.1 to 5.9.1 in production
During the upgrade, apache services are off, so systems will not be able to connect to epo for any policy changes. They will use the policies they already have on their system, so there should be no issues in that regard.
Was my reply helpful? If this information was helpful in any way or answered your question, will you please select Accept as Solution in my reply and together we can help other members?
Don't forget, when your helpful posts earn a kudos or get accepted as a solution you can unlock perks and badges. Those aren't the only badges, either. How many can you collect? Click here to learn more.
Community Help Hub
New to the forums or need help finding your way around the forums? There's a whole hub of community resources to help you.