I found the reason why the wallet was not synchronized.

I outlined the problem here: https://bitcointalk.org/index.php?topic=233997.msg25874905#msg25874905, https://bitcointalk.org/index.php?topic=233997.msg26546800#msg26546800, https://bitcointalk.org/index.php?topic=233997.msg26606174#msg26606174, https://bitcointalk.org/index.php?topic=233997.msg26608073#msg26608073, https://bitcointalk.org/index.php?topic=233997.msg26642100#msg26642100

I took the receiver_76.csv and receiver_77.csv files from http://devcoin.darkgamex.ch/ - the synchronization was stopped on block 303999
Similarly, with receiver_76.csv and receiver_77.csv from https://github.com/Unthinkingbit/charity - there is no synchronization

Today I installed a wallet for Windows and it has downloaded receiver_76.csv and receiver_77.csv. Their size and content differed from the one I downloaded earlier.
I found that receiver_76.csv and receiver_77.csv allowing to synchronize above block 303999 can be downloaded here
http://devcoinpool.btc-music.com/receiver/
http://d.evco.in/receiver/
http://show-me-the-devcoin.info/devtome/
Thus, the contents of these files in different sources differ

In the left panel on the screenshot, the sizes of the receiver_76.csv and receiver_77.csv files with which the synchronization does not stop.
Those on the right are from http://devcoin.darkgamex.ch/ and https://github.com/Unthinkingbit/charity and they do not allow synchronizing the blockchain above block 303999
Because of this, my DVC wallets could not work for quite a long time. Who should I thank for this?