http://idvassilev.blogspot.bg/2018/02/blog-post_22.html
With the help of proxies at highest Bulgarian government level Russia is attempting yet again to force upon Sofia to pay for licenses for Soviet time weapons which will in effect substantial segments of the country's industry under Moscow's control and drastically cut competition from Bulgarian arms manufacturers in the Middle East and elsewhere.
Bulgaria's governments have consistently refused to bow in to Moscow's demands- quoting essential upgrades in the systems and expired license terms. The new government with more openly sympathetic to Moscow ministers of defense and minister of economy might be more willing to accommodate Russia's interests, while seeking to gain in return concessions on the Turkish Stream extension into Bulgaria and Belene NPP.