New player, installed FTC, patch hit, all hell broke loose. I've updated a few section to reference the new DB API changes. I can't say I have all the changes required, but the addon seems to be behaving. If there are other issues and an official update has not been released post and I'll try and figure it out.

Changes so far:

\FoundryTacticalCombat\character\functions.lua

Original:
Line 102: FTC.Target.vlevel = GetUnitVeteranRank('reticleover')
Line 278: FTC.Player.vlevel = GetUnitVeteranRank('player')
Line 282: FTC.Player.vet = GetUnitVeteranPoints('player')
Line 318: local itemLevel = ( GetItemLinkRequiredLevel(GetSlotItemLink(slotNum)) or 0 ) + ( GetItemLinkRequiredVeteranRank(GetSlotItemLink(slotNum)) or 0 )
Line 639: maxExp = 400000
New:
Line 102: FTC.Target.vlevel = GetUnitChampionPoints('reticleover')
Line 278: FTC.Player.vlevel = GetUnitChampionPoints('player')
Line 282: FTC.Player.vet = GetUnitChampionPoints('player')
Line 318: local itemLevel = ( GetItemLinkRequiredLevel(GetSlotItemLink(slotNum)) or 0 ) + ( GetItemLinkRequiredChampionPoints(GetSlotItemLink(slotNum)) or 0 )
Line 639: maxExp = GetNumChampionXPInChampionPoint(FTC.Player.vlevel)

\FoundryTacticalCombat\frames\functions.lua (3 hits)

Original:
Line 120: local level = FTC.Player.vlevel > 0 and "v" .. FTC.Player.vlevel or FTC.Player.level
Line 169: local level = FTC.Target.vlevel > 0 and "v" .. FTC.Target.vlevel or FTC.Target.level
Line 264: local level = GetUnitVeteranRank(unitTag) > 0 and "v" .. GetUnitVeteranRank(unitTag) or GetUnitLevel(unitTag)
New:
Line 120: local level = FTC.Player.vlevel > 0 and "c" .. FTC.Player.vlevel or FTC.Player.level
Line 169: local level = FTC.Target.vlevel > 0 and "c" .. FTC.Target.vlevel or FTC.Target.level
Line 264: local level = GetUnitChampionPoints(unitTag) > 0 and "c" .. GetUnitChampionPoints(unitTag) or GetUnitLevel(unitTag)


\FoundryTacticalCombat\core\events.lua (3 hits)

Original:
Line 62: EVENT_MANAGER:RegisterForEvent( "FTC" , EVENT_VETERAN_RANK_UPDATE , FTC.OnLevel )
New:
Line 62: EVENT_MANAGER:RegisterForEvent( "FTC" , EVENT_CHAMPION_POINT_UPDATE , FTC.OnLevel )


\FoundryTacticalCombat\FoundryTacticalCombat.txt

Original:
Line 3: ## Version: 0.72
Line 4: ## APIVersion: 100014
New:
Line 3: ## Version: 0.73
Line 4: ## APIVersion: 100015

\FoundryTacticalCombat\FoundryTacticalCombat.txt.lua

Original:
Line 18: Author: Atropos / Philgo68
Line 20: Version: 0.72
Line 21: Updated: 2016-03-??
Line 32: FTC.version = 0.72
New:
Line 18: Author: Atropos / Philgo68 / Demiknight (DB Fixes Only)
Line 20: Version: 0.73
Line 21: Updated: 2016-06-16z`
Line 32:FTC.version = 0.73