sharepoint server – Custom Solutions Upgrade is required from SP 2013 to SP 2016?

Hai have SharePoint 2013 Content database required to upgrade to SharePoint 2016,
I started now the Test Upgrade

SP 2013 Farm has deployed Custom Solutions that was targeted to .Net Framework 4.5 my question is when i take backup and deploy in Test SP 2016 farm is these farm solutions works?
Sp2013 Solutions is required to upgrade that SharePoint 2016 built on Microsoft .NET Framework version 4.6?