The tool for sending emails, heirloom-mailx, has been removed in Alpine v3.18.

Please refer to the issue (https://gitlab.alpinelinux.org/alpine/aports/-/issues/14791) and commit (https://gitlab.alpinelinux.org/alpine/aports/-/commit/8f375abf662d2f84ff9b132e8710d6e25eeaf80f) in the Alpine/aports repository for more details.

Although it is possible to lock the Alpine version at 3.17, it is not an ideal solution. I prefer to continue using rclone as the base image, so we need to replace the email sending tool.

I plan to replace heirloom-mailx with s-nail because heirloom-mailx is a stub for s-nail. s-nail maintains a high degree of compatibility, although there may be some incompatible parts, the main options are compatible.

This change will take effect in the next version, and I am currently testing it.

The changes have taken effect in v1.19.0. Here is the s-nail documentation.