In ANSYS Classic, the 2D spar link element (LINK180) may not appear in the list due to version updates, but it can still be accessed through scripting. Users can create this element using the APDL language, as it is not available for selection via the GUI. The command "ET,1,LINK180" sets the element type, allowing for its use despite being unsupported in newer versions. Additionally, users should be cautious about undocumented commands and changes in behavior related to real constants or key options based on their ANSYS version. Legacy elements remain accessible, but users must navigate these complexities to utilize them effectively.