Please help us help you and fill where relevant:
Your LimeSurvey version: [see right hand bottom of your LimeSurvey admin screen]
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Survey theme/template: Limesurvey 2.06 build 160129
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Hi,

Does Limesurvey 2.06 build 160129 support php 7.4 ?

Thank you very much.

Alexandre

I am not sure, but do you realize that you are running a huge risk, using a LimeSurvey version that is from 29 January 2016?

In these ages that is ancient.

Tammo