OpenTofu 1.13 adds assume functions to handle unknown plan values

OpenTofu 1.13 shipped on September 30, with a 1.13.1 patch on October 1 and security support through August 2027. The headline feature is the assume family of functions (assumenotnull, assumestringprefix, assumeequal, convert), which let module authors tell the planner what they know about values marked (known after apply). OpenTofu verifies those assumptions at apply time, so a wrong promise fails the apply.

• OpenTofu 1.13 shipped September 30, patch 1.13.1 on October 1, support to August 2027
• assume functions declare properties of unknown values and are checked at apply
• Adds experimental linting via tofu plan -lint=all and Symbol Libraries
• Windows on ARM64 is now official; final release with 32-bit builds