I've used and loved this mod for a couple of years now, but I just started choosing mods for a new Krastorio 2 run and it just won't load, though AFH does without a problem. Here is the relevant error message from the log file:

Error while running setup for entity prototype "underground-i-t2-pipe" (pipe-to-ground): next_upgrade target (underground-i-t3-pipe) must have an item that builds it that isn't hidden.

Here is the list of mods I'm running. Any ideas?:

https://mods.factorio.com/mod/base
https://mods.factorio.com/mod/aai-containers
https://mods.factorio.com/mod/AbandonedRuins
https://mods.factorio.com/mod/AbandonedRuins-Krastorio2
https://mods.factorio.com/mod/Akimbo-Pistols
https://mods.factorio.com/mod/AmmoGroup
https://mods.factorio.com/mod/ArtillerySwitchUpdated
https://mods.factorio.com/mod/assembler-pipe-passthrough-v2
https://mods.factorio.com/mod/atan-null
https://mods.factorio.com/mod/auto-research
https://mods.factorio.com/mod/AutoDeconstruct
https://mods.factorio.com/mod/autodrive
https://mods.factorio.com/mod/automatic-underground-pipe-connectors
https://mods.factorio.com/mod/auto_deconstruct_loot_reconstructed
https://mods.factorio.com/mod/auto_manual_mode
https://mods.factorio.com/mod/Babelfish
https://mods.factorio.com/mod/ballistics
https://mods.factorio.com/mod/barreling-machine
https://mods.factorio.com/mod/barrels-o-fuel
https://mods.factorio.com/mod/belt-balancer-performance
https://mods.factorio.com/mod/BeltLineUpgrade
https://mods.factorio.com/mod/better-victory-screen
https://mods.factorio.com/mod/big-mining-drill
https://mods.factorio.com/mod/BottleneckLite
https://mods.factorio.com/mod/bullet-trails
https://mods.factorio.com/mod/chunk-aligned-roboports
https://mods.factorio.com/mod/compaktcircuit
https://mods.factorio.com/mod/concentrated-solar-power
https://mods.factorio.com/mod/copy-machine-orientation
https://mods.factorio.com/mod/CopyPasteModules
https://mods.factorio.com/mod/Cursor_Craft
https://mods.factorio.com/mod/deadlock-beltboxes-loaders
https://mods.factorio.com/mod/DeadlockBlackRubberBelts
https://mods.factorio.com/mod/DeadlockStackingForDeepCoreMining
https://mods.factorio.com/mod/deadlock_stacked_recipes
https://mods.factorio.com/mod/DedLib
https://mods.factorio.com/mod/DestructiveBlueprints
https://mods.factorio.com/mod/DiscoScience
https://mods.factorio.com/mod/discovery_tree
https://mods.factorio.com/mod/early-logistics11
https://mods.factorio.com/mod/EpicWeaponSounds
https://mods.factorio.com/mod/equal-length-underground-belts
https://mods.factorio.com/mod/EquipmentGridLogisticModule
https://mods.factorio.com/mod/even-distribution
https://mods.factorio.com/mod/Exoskeleton%20Mark%20II
https://mods.factorio.com/mod/extra-underground-belt-pair
https://mods.factorio.com/mod/factorissimo-2-notnotmelon-surfaceAPIfix
https://mods.factorio.com/mod/FactorySearch
https://mods.factorio.com/mod/Fill4Me-fixed
https://mods.factorio.com/mod/filter-helper-helper
https://mods.factorio.com/mod/FilterHelper
https://mods.factorio.com/mod/filter_assistant
https://mods.factorio.com/mod/fireproof-worker-bots
https://mods.factorio.com/mod/flib
https://mods.factorio.com/mod/FNEI
https://mods.factorio.com/mod/GDIW
https://mods.factorio.com/mod/Generic_Logistic_Chest
https://mods.factorio.com/mod/GhostOnWater
https://mods.factorio.com/mod/gunturret-require-smg
https://mods.factorio.com/mod/HandCraftingPriorityPlus
https://mods.factorio.com/mod/helmod
https://mods.factorio.com/mod/inbuilt_lighting
https://mods.factorio.com/mod/inventory-repair
https://mods.factorio.com/mod/jet-fuel
https://mods.factorio.com/mod/K2_Black_Rubber_Belts
https://mods.factorio.com/mod/K2_StarCraft_SFX
https://mods.factorio.com/mod/kj_factorissimo_hr
https://mods.factorio.com/mod/kr-air-purifier-helper
https://mods.factorio.com/mod/Krastorio2
https://mods.factorio.com/mod/Krastorio2Assets
https://mods.factorio.com/mod/Kux-CoreLib
https://mods.factorio.com/mod/Kux-GhostInHand
https://mods.factorio.com/mod/Kux-SpeedButtons
https://mods.factorio.com/mod/Kux-Zooming
https://mods.factorio.com/mod/larger_shortcut_icons
https://mods.factorio.com/mod/LessUnplugged_bud
https://mods.factorio.com/mod/light-overhaul
https://mods.factorio.com/mod/lightArtillery
https://mods.factorio.com/mod/logistic-mall-assembling-machine
https://mods.factorio.com/mod/LogisticRequestManager
https://mods.factorio.com/mod/logistics_requests_sorted
https://mods.factorio.com/mod/logtech-beacon-edit
https://mods.factorio.com/mod/Long_Range_Delivery_Drones
https://mods.factorio.com/mod/manual-inventory-sort
https://mods.factorio.com/mod/ManualLogistics
https://mods.factorio.com/mod/markers
https://mods.factorio.com/mod/Mineable-Cliffs
https://mods.factorio.com/mod/mining-patch-planner
https://mods.factorio.com/mod/Module-Rebalance
https://mods.factorio.com/mod/ModuleInserterEx
https://mods.factorio.com/mod/MouseOverConstruction
https://mods.factorio.com/mod/m_WhereIsMyBody
https://mods.factorio.com/mod/nco-LongStorageTanks
https://mods.factorio.com/mod/nicefill-scriptfix
https://mods.factorio.com/mod/NindyCore
https://mods.factorio.com/mod/ore-washing
https://mods.factorio.com/mod/PickerAtheneum
https://mods.factorio.com/mod/PickerDollies
https://mods.factorio.com/mod/PickerInventoryTools
https://mods.factorio.com/mod/PickerPipeTools
https://mods.factorio.com/mod/pigo-selector-combinator
https://mods.factorio.com/mod/ping-dont-blink
https://mods.factorio.com/mod/placeonconcrete
https://mods.factorio.com/mod/pollution-scaling
https://mods.factorio.com/mod/power-grid-comb
https://mods.factorio.com/mod/Prettier-Stacked-Ores-1_1
https://mods.factorio.com/mod/ProgressiveRunningRevived
https://mods.factorio.com/mod/railloader-MXO
https://mods.factorio.com/mod/rangeindicators_ht
https://mods.factorio.com/mod/RealisticDecorationCleanup
https://mods.factorio.com/mod/redo
https://mods.factorio.com/mod/research-desk
https://mods.factorio.com/mod/Robot256Lib
https://mods.factorio.com/mod/robotworld-continued
https://mods.factorio.com/mod/Rocket-Silo-Construction
https://mods.factorio.com/mod/romulinhosresearchqueuealwaystrue
https://mods.factorio.com/mod/rs-beacon-counter
https://mods.factorio.com/mod/rusty-locale
https://mods.factorio.com/mod/rusty-locale-xeraph
https://mods.factorio.com/mod/sacrificial-research
https://mods.factorio.com/mod/scattergun_turret
https://mods.factorio.com/mod/Shortcuts-ick
https://mods.factorio.com/mod/shortwave_fix
https://mods.factorio.com/mod/show-max-underground-distance
https://mods.factorio.com/mod/silent-filter-combinator
https://mods.factorio.com/mod/simhelper
https://mods.factorio.com/mod/single-storage-system
https://mods.factorio.com/mod/small-iron-pole
https://mods.factorio.com/mod/SmallRobots
https://mods.factorio.com/mod/Smart_Inserters
https://mods.factorio.com/mod/Smooth_Fluids
https://mods.factorio.com/mod/spill_inventory
https://mods.factorio.com/mod/Squeak%20Through
https://mods.factorio.com/mod/StableFoundations
https://mods.factorio.com/mod/Stacked_Mining
https://mods.factorio.com/mod/staggering_force
https://mods.factorio.com/mod/status_bars
https://mods.factorio.com/mod/stdlib
https://mods.factorio.com/mod/SunBarSwap
https://mods.factorio.com/mod/Switch_Button-1_0
https://mods.factorio.com/mod/Switch_Button_Retexture
https://mods.factorio.com/mod/TacticalConstruction
https://mods.factorio.com/mod/TemporaryLogisticRequest
https://mods.factorio.com/mod/TintedGhosts
https://mods.factorio.com/mod/tiny-assemblers
https://mods.factorio.com/mod/train-pubsub
https://mods.factorio.com/mod/train-station-skip
https://mods.factorio.com/mod/TrainBigCarriage
https://mods.factorio.com/mod/TrainGroups
https://mods.factorio.com/mod/TrainSpeeds
https://mods.factorio.com/mod/Train_Control_Signals_SE
https://mods.factorio.com/mod/TSM-outpost-builder
https://mods.factorio.com/mod/TSM_Helper
https://mods.factorio.com/mod/TurretPod
https://mods.factorio.com/mod/underground-pipe-pack
https://mods.factorio.com/mod/underground-power-lines
https://mods.factorio.com/mod/Upgraded-Robots
https://mods.factorio.com/mod/vehicle-corpses
https://mods.factorio.com/mod/VehicleSnap
https://mods.factorio.com/mod/vtk-deep-core-mining
https://mods.factorio.com/mod/WaterPumpjack
https://mods.factorio.com/mod/WellPlanner_bzgas_fixed
https://mods.factorio.com/mod/WideChests
https://mods.factorio.com/mod/WideChestsLogistic
https://mods.factorio.com/mod/WideChests_AAI_Containers_Fix
https://mods.factorio.com/mod/WireShortcutX
https://mods.factorio.com/mod/Workbench
https://mods.factorio.com/mod/wret-beacon-rebalance-mod
https://mods.factorio.com/mod/zzzzStopChasingBeltItems

same here, but with much less mods. Looks forward to fix ;)

This isn't a mod conflict. The base mod Advanced Fluid Handling has been updated to make the upgrade planner work to upgrade from Tier 1 to 2 and 3 now. This was about a week ago. In the meantime, you can fix it by replacing your local version of Advanced Fluid Handling with 1.1.2, downloaded manually from the site and then not updating it again until this mod has accounted for it.

This isn't a mod conflict. The base mod Advanced Fluid Handling has been updated to make the upgrade planner work to upgrade from Tier 1 to 2 and 3 now. This was about a week ago. In the meantime, you can fix it by replacing your local version of Advanced Fluid Handling with 1.1.2, downloaded manually from the site and then not updating it again until this mod has accounted for it.

Thanks for letting us know!