← All Sidereal Confluence questions

Can you upgrade a card that another player lent or traded to you, or use a borrowed technology to upgrade your own card?

No. Both the upgrading card and the spent card must be in your possession, not loaned to another player, so a borrowed technology or converter cannot be spent for an upgrade and cannot itself be upgraded. An opponent's technology is always returned to its owner. The owner can run the upgrade for you if you give them the resources, and can upgrade a card traded back to them if both players agree.

More Sidereal Confluence questions · Full rulebook