This article discusses the potential issues and challenges for the upgradation and migration of the next-generation optical network

and proposes the strategies of tackling these.Due to the increasing bidirectional asymmetry of traffic flows

we propose to separate the pair of transmitter and receiver in each optical transponder to encapsulate them in independent modules.To support the smooth migration from the Dense Wavelength Division Multiplexing（DWDM）optical network to the flexiblespectrum optical network

we propose to employ the sub-band virtual concatenation technique to enable the transmission of super-channels in the DWDM network.We also discuss the strategies of using the new generation of colorless

directionless

contentionless

and gridless Reconfigurable Optical Add/Drop Multiplexer（ROADM）to replace old ROADM in the optical network.In addition

the issues on enabling the communications between the new and old generations of ROADMs is also discussed.Finally

considering the reality that a large amount of fibers would be replaced in the coming years

we consider the issues and strategies of replacing old single-mode fibers with the new large effective area and ultra-low loss fibers.