Always check the Cisco Release Notes for version 7.18 before upgrading to ensure there are no "Caveats" (known bugs) that might affect your specific configuration.
Alternatively, via SCP for security:
: Requires Oracle JRE 8.0 (version 8u261 or later) or OpenJRE 1.8.x. How to Download and Install Cisco ASDM 7.18 cisco asdm 7.18 download
(Note: Manual web download is more common; direct CLI often requires a direct support contract link.) Always check the Cisco Release Notes for version 7