Microsoft’s strategy has shifted entirely toward cloud-first, subscription-based services. By 2021, Office 2013 was two full generations behind (Office 2016 and Office 2019 had been released, and Office 2021 was launching later that year). Supporting legacy Language Packs incurred maintenance costs for download servers, digital certificate renewals, and security patching.

To maintain compatibility and security (especially for connecting to services like Microsoft 365 Exchange), Service Pack 1 (SP1) was mandatory as of late 2021. How to Obtain the Lithuanian Language Pack

Microsoft Office 2013 Lithuanian Language Pack — Installation, Activation, and Troubleshooting (2021 Guide)