# Error: Conflicting version constraints for module 'vpc': required_version = ">= 1.6, < 2.0" but other module requires ">= 1.5, < 1.8"

- **ID:** `terraform/conflicting-terraform-version-constraints`
- **Domain:** terraform
- **Category:** config_error
- **Verification:** ai_generated
- **Fix Rate:** 80%

## Root Cause

Multiple modules define overlapping but conflicting required_version constraints, making it impossible to select a single Terraform version that satisfies all.

## Version Compatibility

| Version | Status | Introduced | Deprecated |
|---------|--------|------------|------------|
| Terraform v1.5 | active | — | — |
| Terraform v1.6 | active | — | — |
| Terraform v1.7 | active | — | — |

## Workarounds

1. **Align all module required_version constraints to a single compatible range. For example, change all to required_version = ">= 1.6, < 2.0". Then run 'terraform init -upgrade' to reinitialize.** (85% success)
   ```
   Align all module required_version constraints to a single compatible range. For example, change all to required_version = ">= 1.6, < 2.0". Then run 'terraform init -upgrade' to reinitialize.
   ```
2. **If alignment is not possible, remove required_version from conflicting modules and rely on root module's constraint. Edit each module's versions.tf to delete the required_version line, then run 'terraform init'.** (75% success)
   ```
   If alignment is not possible, remove required_version from conflicting modules and rely on root module's constraint. Edit each module's versions.tf to delete the required_version line, then run 'terraform init'.
   ```

## Dead Ends

- **** — Root module constraints are combined with child module constraints; overriding doesn't work because Terraform enforces intersection of all constraints. (95% fail)
- **** — Removing constraints from child modules may cause them to be used with incompatible Terraform versions, leading to other errors. Terraform still validates root constraints. (70% fail)
- **** — This doesn't resolve existing conflicts; it may introduce new ones if modules have different minimum version requirements. (85% fail)