Hi folks, now is as good a time as any for some good news!
We now have the ability to allow people to play old replay files, after new builds are pushed.
HOLY WHOA PUDDING GARDENING NO WAY?!
Way. But there are still some restrictions, and the system is by no means perfect - so please read below before you run around fist-pumping into the air in excitement:
This is not a backwards compatibility replay system. No Timey Wimey, Wibbly Wobbly.
What does that mean? It means that really old replays still won't load. If there is a significant buff or nerf to something in a build, odds are files before that won't behave properly.
Okay, so why is this a big deal?
What this DOES mean, is that in situations where we push minor builds (like today) where balance is not impacted, your replays are not entirely lost. You will see a 'sync error' message displayed over the replay, but they will still be watchable. We are investigating how to resolve the 'sync error' message in the future - but for now, at least the replays can be viewed! We are taking steps in the right direction. This has been something the team has been working on for a while - we've heard your comments and concerns on this.
When will this be in the game?
As soon as our servers come back up from maintenance tonight (When will that be? Not entirely sure, but we will keep you guys posted)
The Butterfly Effect, But No Ashton Kutcher (Sorry, or You're Welcome?)
Really old replays may crash your game. Anything beyond the October patch will likely encounter problems. As time goes on, we will work to further refine this. The 'sort of' technical explanation is as follows: A replay is a file that has step by step instructions regarding how to direct the AI in order to reproduce a certain match. It doesn't save things like unit values, so if a significant nerf or buff has occurred since that replay, when the AI tries to play the game strange things will happen and may eventually result in a crash. Units that died may somehow survive... you'll potentially see some 'alternate universe' stuff go down, then a crash. But for updates where no balance changes are made, that instead focus on bug fixes, adding a faceplate, et cetera - this will allow you to still review your replays.
Here's the nitty gritty:
Known issues: Sync error detected warning is displayed continually.
Steps:
Right click on COH2 install in steam games list
Select properties
Select launch options
Enter –allowIncompatibleReplays (include the dash, no spaces)
Click OK, and launch COH2
All replays in playback folder should now appear in replay list UI
source:
http://community.companyofheroes.com/forum/company-of-heroes-2/company-of-heroes-2-general-discussion/122894-replays-an-update-time-for-some-good-news