As the title suggests, in my present (and first) playthrough, I noticed that all the upgrade prices (both gold- and material-wise) have doubled for unique items I acquire after the patch. All of the items I already had before the patch have retained their upgrade prices. As an example four screenshots of Watershaper's Focus I acquired after the patch and a screenshot of Gladiator Sword I got before the patch:
https://steamuserimages-a.akamaihd.net/ugc/937195636674095942/CDF2728E736FC7361A51BBC6512D95F6FB4CB883/
https://steamuserimages-a.akamaihd.net/ugc/937195636674096400/2928DD1A17C98C160C96EA03D44DBD06D1E9989C/
https://steamuserimages-a.akamaihd.net/ugc/937195636674095599/3E4E66693B4659F2F7FF01DAE7B5ACDD1B8B5560/
https://steamuserimages-a.akamaihd.net/ugc/937195636674095201/C3E8C34DA05505067ADB30B3B33984EFD7FFE123/
https://steamuserimages-a.akamaihd.net/ugc/937195636674090618/7FDB0A7D8E2DFCFD49514D854700F28DF850C507/
I would attach a savegame, but filesize is limited to 507 kBytes, so...
P.S.
Please don't "balance" this game into a gray homogeneous goo mechanic-wise and try to respect the time of your playerbase.
