I have to update my existing Sharepoint (2013) List with data from an Excel Sheet. I've only found an old Add-In for Sharepoint 2007. Which other possibilities do I have?
You could try the App Store:
Program it yourself
- with Powershell
Use MS-Access and some basic SQL statements
- or VBscript
How long is the list you want to add? If it's not that long then i think the best way is to copy and then past in the 2013 list using edit mode. Using other ways may cause damage. The thing is that you should compare the two lists in order for them to have the same column in order then put your list on edit mode, copy any number of rows (or columns) using Ctrl + c, click once on the first box and then past using Ctrl + v. If it doesn't work the first time copy less and for the second time copy more.
You can do this with third party tools: export your list to Excel, change whatever you need in Excel and sync your changes back to SharePoint.
I suggest having a look at SharePoint List Synchronizer (disclaimer: I work for SoftFluent, the company that developed this tool). If your need is one time only, this is doable within the trial period (= for free).
Worth noting that there is no server side setup. It's client only.