The PLC was an old S7-1200. The HMI was a rust-stained TP700. And the only backup program in existence was a file named Bottling_Line_V11.zap13 .
She needed . Not V12. Not V13. Specifically SP2. tia portal v11 sp2 download
But the portal only showed V16 and above. It was as if V11 had been erased from history. The PLC was an old S7-1200