CMS based web sites should never go online without a security maintenance plan.
If you'r website software is not maintained it's vulnerable for hacking.
Software vulnerabilities are the main reason leading to hacked web sites. Fixing the hack is pricy compared to the security maintenance not to mention the loss of reputation, Google search rank or valuable data.
It's fairly easy to keep your TYPO3 CMS up to date. It has to be monitored and patched as soon as the fixes have been released. There's no IF's, maintenance plan has to be sorted out before your site goes online.
Some of our clients have been with us for as long as 10 years already. Websites have gone through multiple desing updates, becoming mobile friendly and all that. Behind it there's always up to date and secure TYPO3 version to support those modern technologies.
Just get in touch and we can discuss the possible maintenance solution best for your web application.