Redmine

Hello.
I think you can do above request with using jQuery.

// I’m sorry this may be not elegant example....
$(function() {
    const HOURS_AS_LATEST = 24; 
    var updates = $('tr.issue td.updated_on');
    var today = new Date();
    var diff = 60*60*1000*HOURS_AS_LATEST;
    updates.each(function(i,issue) {
            var t = new Date($(issue).text());
            var msDiff = today - t;
            if (msDiff <= diff) {
                $(issue).parent().css('background-color', '#ffa0a0');
            }
        }
    );
});

Please NOTE:

Please note if you try above approach, date format needs follow IETF RFC 2822 Date and Time Specification. If date format you use is different format, date parse function might not work correctly. When following ISO 8601, some browser such as IE also does not work correctly.

I recommend you to use View Customize plugin, if you could install additional plugin :)

This plugin allows you to customize the view for the Redmine, with using additional css / JavaScript.
To define additional css / Javascript, you don't have to edit Redmine’s CSS or JS files on filesystem directly.
You can input and register them from Administration Web form.

• https://redmine.org/plugins/redmine_view_customize
• https://github.com/onozaty/redmine-view-customize

Followings are sample screenshots.

I hope this would be any help.

I really like this unread_issues plugin. Every user has their own 'view' of the issues as follows -

green - new issue
blue - updated issue

v useful - https://www.redmine.org/plugins/unread_issues