[BLOCKING LIVE CONTENT] worlds crash on startup

Verification builds
1.4.0 (853103)

Summary
opening live content from the marketplace pops an assert error and crashes the game

Impact
"My Snowy Journey", "My Gorilla Adventure" and "Desert of Secrets" worlds currently live on the marketplace

Repro Steps
1. download "My Snowy Journey" or "My Gorilla Adventure" or "Desert of Secrets"
2. create a new world from the template
3. open it

Observed Results
an assertion error pops up on "My Snowy Journey" and "My Gorilla Adventure":

Assertion failed: This field is no longer supported, please remove @ mce::RenderMaterial::parseTextures

Function: in F:\DarwinWork\7\s\handheld\project\VS2015\systems\Renderer\Renderer.Shared\..\..\..\..\..\src-deps\Renderer\RenderMaterial.cpp @ 788

assertion error pops up on "Desert of Secrets":

Assertion failed: must have at least 1 recieve.

Condition is false: !trade.mReceive.empty()

Function: parseAllTradeJson in F:\DarwinWork\7\s\handheld\project\VS2015\Minecraft\Minecraft.Shared\..\..\..\..\src\common\world\item\trading\TradeTables.cpp @ 173

Expected Results
world start without errors and allows the player to keep playing normally

Platform
Windows 10 on PC