Today I received this resonse to uploading new package qemu:
Version check failed:
Your upload included the binary package qemu-system-x86, version 1:2.12+dfsg-1pureos1, for amd64,
however landing already has version 1:2.12+dfsg-1+b1.
Uploads to landing must have a higher version than present in landing.
Seems to me + should win over bare ""1" but not over "1pureos1".