Notice how BTC's all time high hit the upper 0.5 warning line (dotted lines are 0.25 levels, and solid lines are 0.5 levels) almost perfectly. Price has since retracted to test the , which is what we would expect of the correction from the ATH in any trading vehicle.
Not a whole lot of channeling has occurred within the levels, but there was some, and price definitely did react to the levels, putting in at, or very near, the lines.
Since price has recently broken down through the , the next support is the lower 0.25 parallel line (the dotted line right below the current price). However, we can't predict how strong of support it will be as price got little reaction out of it in the past. If you look back to the 2012 to 2013 period you can see that price put in a high from a test of that level to later pierce it, without much, if any, re-testing of that level.
The lower 0.5 parallel line (the first solid line below the current price), on the other hand, does appear to be a strong S/R line, as price had a lot of reaction to it during that same time window. It appeared to act as a line of symmetry to the price, attracting it back after short term gyrations. That might just be the line that price wants to follow long-term.
That being said, price will likely throw in some more tests on the in the future. It may happen a few days out, or it may happen 2 or 3 years out. It's not common that a be tested from above like it was here without it being tested again a few times from below (as is the case with a horizontal S/R line).
Should the price come back to test the around the first day of 2017, that test would happen at around $900/ BTC .