When running any NixOps operation with a more recent revision of nixpkgs, I get the following output:

trace: warning: The args argument to evalModules is deprecated. Please set config._module.args instead.
trace: warning: The check argument to evalModules is deprecated. Please set config._module.check instead.
trace: warning: The args argument to evalModules is deprecated. Please set config._module.args instead.
trace: warning: The check argument to evalModules is deprecated. Please set config._module.check instead.
trace: warning: The args argument to evalModules is deprecated. Please set config._module.args instead.
trace: warning: The check argument to evalModules is deprecated. Please set config._module.check instead.
trace: warning: The args argument to evalModules is deprecated. Please set config._module.args instead.
trace: warning: The check argument to evalModules is deprecated. Please set config._module.check instead.
trace: warning: The args argument to evalModules is deprecated. Please set config._module.args instead.
trace: warning: The check argument to evalModules is deprecated. Please set config._module.check instead.
trace: warning: The args argument to evalModules is deprecated. Please set config._module.args instead.
trace: warning: The check argument to evalModules is deprecated. Please set config._module.check instead.
trace: warning: The args argument to evalModules is deprecated. Please set config._module.args instead.
trace: warning: The check argument to evalModules is deprecated. Please set config._module.check instead.
trace: warning: The args argument to evalModules is deprecated. Please set config._module.args instead.
trace: warning: The check argument to evalModules is deprecated. Please set config._module.check instead.
trace: warning: The args argument to evalModules is deprecated. Please set config._module.args instead.
trace: warning: The check argument to evalModules is deprecated. Please set config._module.check instead.
trace: warning: The args argument to evalModules is deprecated. Please set config._module.args instead.
trace: warning: The check argument to evalModules is deprecated. Please set config._module.check instead.
trace: warning: The args argument to evalModules is deprecated. Please set config._module.args instead.
trace: warning: The check argument to evalModules is deprecated. Please set config._module.check instead.
trace: warning: The args argument to evalModules is deprecated. Please set config._module.args instead.
trace: warning: The check argument to evalModules is deprecated. Please set config._module.check instead.